Electrical Operation Manual handbook

Electrical Operation Manual

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Contents

Chapter I Primary Wiring System ........................................................................................................... 7 1 Electrical Primary Wiring ......................................................................................................... 7

1.1 Main Electrical Primary Wiring ............................................................................... 7 1.2 Auxiliary Power Connection ..................................................................................... 7

2 Operation Modes of Systems ....................................................................................................... 8 2.1 150KV System.................................................................................................................... 8 2.2 Auxiliary Power System.................................................................................................. 10

Chapter II Generator ............................................................................................................................... 11 1 Equipment Specifications .......................................................................................................... 11

1.1 Generator Nameplate Parameters ................................................................................. 11 1.2 Design Specification of Generator ................................................................................. 11 1.3 Technical Characteristics of Generator......................................................................... 12 1.4 Basic Technical Requirements ........................................................................................ 13 1.5 Structure of Generator Body .......................................................................................... 13 1.6 Cooling System of Generator ......................................................................................... 15 1.7 Generator Excitation System ......................................................................................... 17

2 Operation and Maintenance...................................................................................................... 23 2.1 Check and Preparation Work before Steam Turbine Generator Startup .................. 23 2.2 Workings after Impulse Starting of Steam Turbine ..................................................... 25 2.3 Operations........................................................................................................................ 25 2.4 Normal Operation Mode of Generator ......................................................................... 27 2.5 Monitoring in Operation ................................................................................................ 29 2.6 Parallel Off and Shutdown of Generator ...................................................................... 31 2.7 Maintenance after Shutdown ......................................................................................... 33 2.8 Accident Handling ........................................................................................................... 35

1 Equipment Specifications .......................................................................................................... 42 1.1 Equipment Technical Parameters of Main Transformer ............................................. 42 1.2 Equipment Technical Parameters of HV Auxiliary Power Transformer ................... 42 1.3 Equipment Technical Parameters of Startup Standby Transformer .......................... 43 1.4 Technical Parameters of LV Auxiliary Power Transformer ........................................ 44

2 Manual for Transformer Operation ......................................................................................... 44 2.1 Manual for Normal Operation Temperatures of Transformers ........................... 45 2.2 Manual for Transformer Insulations ...................................................................... 45 2.3 Manual for Normal Operation Voltage of Transformer ....................................... 46 2.4 Operation Instructions for Voltage Regulating Device ......................................... 46 2.5 Parallel Operation of Transformers ....................................................................... 47 2.6 Manual for Overload Operation of Transformer .................................................. 47 2.7 Operation of Transformer Cooling Device ............................................................. 48 2.8 Operation Manual of Transformer Gas Protection ...................................................... 49 2.9 Manual for Neutral Point Earthing of Startup Standby Transformer ....................... 50 2.10 Neutral point earthing resistance cabinet of HV auxiliary power transformer,

startup standby transformer ................................................................................... 50 3 Checks and Tests of Transformer ........................................................................................... 51

3.1 Checks and Tests before Transformer Putting into Operation ............................ 51 3.2 Check of Transformer in Operation .............................................................................. 52


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3.3 Special Check of Transformer ........................................................................................ 52 3.4 Check Items for Dry Transformer ................................................................................. 53

4 Transformer Putting In or Out of Operation ........................................................................ 53 4.1 Transformer Putting Into Operation ...................................................................... 53 4.2 Transformer Out of Operation................................................................................ 54

5 Abnormal Operation and Accident Handling of Transformer ............................................ 54 5.1 A transformer must immediately stop operating when the transformer occurs

one of the following conditions. ............................................................................... 54 5.2 When a transformer takes place one of the following conditions, it is permitted

to outage after reporting; if the condition is permissible, the standby transformer can be changed over. ........................................................................... 54

5.3 Transformer Overload ............................................................................................. 55 5.4 Transformer Temperature High.............................................................................. 55 5.5 Handling for Transformer Gas Protection Action ................................................. 55 5.6 Handling for Transformer Differential Protection Action .................................... 56 5.7 Handling for Transformer Overcurrent Protection Action .................................. 57 5.8 A Mass of Oil Leakage of Transformer .................................................................. 57 5.9 Handling for Transformer Catching Fire ............................................................... 57

Chapter IV Distribution Device Manual ................................................................................................ 59 1 Equipment Specification of Distribution Devices .................................................................. 59

1.1 Technical Parameters of HV Sulfur Hexafluoride Circuit Breaker for ZF9-252/Y4000-50 Gas Insulation Metal Enclosed Switchgear (GIS) ...................... 59

1.2 Rated Insulation Level ............................................................................................. 60 1.3 SF6 Pressure Parameters (at 20℃) ......................................................................... 60 1.4 Parameters of Control Circuits and Auxiliary Circuits ........................................ 60 1.5 Technical Parameters of ZF9-252/Y4000-50 GIS Isolating switch ...................... 60 1.6 Technical Parameters of Overhaul Earthing Switch Used for ZF9-252/Y4000-50

GIS ............................................................................................................................. 61 1.7 Technical Parameters of Fault Closing Earthing Switch Used for

ZF9-252/Y4000-50 GIS ............................................................................................ 61 1.8 BANTEN 2×300MW CFSPP Station ...................................................................... 62 1.9 Technical Parameters of Voltage Transformer JDQX8-150ZHA1....................... 62 1.10 Technical Parameters of Enclosed Busbar ............................................................. 62 1.11 Micro Positive Pressure Device of Enclosed Busbar ............................................. 62 1.12 Technical Parameters of Branch Circuit Enclosed Busbar .................................. 63 1.13 Detailed Parameters of Micro Positive Pressure system ....................................... 63 1.14 Excitation transformer, generator neutral point grounding transformer, risistance

and current transformer .......................................................................................... 63 2 Operation and Maintenance of Distribution Devices .............................................................. 63

2.1 General Manual for Distribution Devices ..................................................................... 63 2.2 Patrol Inspection of Contribution Devices .................................................................... 64 2.3 Normal Operation and Maintenance of Cable ............................................................. 65 2.4 Operation Maintenance of Isolating Knife Switch and Busbar .................................. 66 2.5 Operation and Maintenance of Instrument Transformer ........................................... 67 2.6 Operation and Maintenance of Lightning Arrestor ..................................................... 67 2.7 Operation and Maintenance of Enclosed Busbar ......................................................... 67 2.8 Operation and Maintenance of Trolley Type Switchgear ............................................ 68


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2.9 Operation Manual for Auxiliary Power 6KV System Vacuum Switch and Vacuum Contactor (F-C Circuit Switch) ............................................................................... 69

2.10 Manual for Check and Operation of GIS Combined Electrical Equipment ........... 70 3 Abnormal Operation and Accident Handling for Switchgear ............................................... 72

3.1 General Principle of Accident Handling ....................................................................... 72 3.2 Accident Handling Procedures....................................................................................... 72 3.3 In case of any of the following emergency situations, operators may firstly deal with

it and then report to the shift supervisors: ............................................................. 73 3.4 Manual on Accident Handling ....................................................................................... 73 3.5 Accident handling to abnormal system frequency ....................................................... 73 3.6 Accident Handling to Abnormal System Voltage ......................................................... 74 3.7 Power system oscillation ................................................................................................. 74 3.8 Busbar failure .................................................................................................................. 75 3.9 Line tripped ..................................................................................................................... 75 3.10 SF6 Circuit-breaker refusal to trip .............................................................................. 76 3.11 Lower Gas Pressure in SF6 Circuit-breakers ............................................................. 76 3.12 SF6 Circuit-breaker Failure to Close .......................................................................... 77 3.13 On-load closing isolators or closing isolators with earthing conductor .................... 77 3.14 ON-load opening isolators ............................................................................................ 77 3.15 Blown PT fuse ................................................................................................................ 78 3.16 Open circuit of CT’s secondary side ............................................................................ 78 3.17 Immediately disable PTs and CTs in case of any of the following conditions. ......... 78 3.18 Lightning arrester failure ............................................................................................. 78

4 Accident handling to auxiliary power supply system failure ................................................. 78 4.1 General principle of accident handling ......................................................................... 78 4.2 Total loss of auxiliary power........................................................................................... 79 4.3 6kV busbar failure........................................................................................................... 79 4.4 Damage of 6kV withdrawable switch ............................................................................ 80 4.5 Tripping of Miniature Switches on 6lV PT Secondary Side ........................................ 80 4.6 Automatic circuit-breaker tripping ............................................................................... 80 4.7 Circuit-breaker Refusal to Close ................................................................................... 81 4.8 Circuit-breaker Refusal to Open ................................................................................... 81 4.9 Circuit-breaker Failure to Close .................................................................................... 81 4.10 380V busbar failure ....................................................................................................... 82 4.11 Broken 380V Voltage Circuit ........................................................................................ 82 4.12 Overcurrent of Certain 380V Section .......................................................................... 82 4.13 Immediately de-energize the cables in case of any of the following conditions: ...... 83 4.14 Cable Catching Fire ...................................................................................................... 83

Chapter V Electric Motor ........................................................................................................................ 84 1 Equipment Specification ............................................................................................................ 84 2 Motor Operation and Maintenance .......................................................................................... 84

2.1 General Provisions on Motors ........................................................................................ 84 2.2 Provisions on Motor Operation ...................................................................................... 85

3 Motor Patrol Inspection and Maintenance .............................................................................. 87 3.1 Inspection Prior to Motor Startup ................................................................................. 87 3.2 Inspection during Motor Operation .............................................................................. 87


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4 Abnormal Operation and Accident Handling for Motors .................................................... 88 4.1 Motors Tripped during Operation ................................................................................. 88 4.2 Motors are Tripped Immediately after Circuit-breakers are Closed ......................... 89 4.3 The Quick-breaking or Overload Protection is Triggered when Motors Start up after

Installation or Maintenance .................................................................................... 89 4.4 After motor circuit-breakers are closed, the rotors remain standstill or the speed

can not reach the rated value, abnormal noise is heard, the motor current is zero or remain at the full scale value of ammeters for more than normal time. ......... 89

4.5 During motor operation, running noise changes, running speed drops and motor current abnormally rise or drop to zero. ................................................................ 90

4.6 The stator current undergoes cyclic swing during motor operation. ................... 90 4.7 Motors are overloaded ............................................................................................. 91 4.8 The motor stator temperature sharply rises and exceed the rated values.................. 91 4.9 Abnormal Vibration ................................................................................................. 91 4.10 Bearing Overheating ................................................................................................ 91 4.11 Slide rings, brush holders and brush frames are overheated during the

operation of wound rotor type motors .................................................................... 92 4.12 Dealing with Motors Catching Fire ........................................................................ 92

Chapter VI DC, Emergency and UPS Power Supply System .............................................................. 93 1 Equipment Specification for DC Systems ................................................................................ 93

1.1 JZ-BPD-Ⅲ smart battery monitor ............................................................................... 93 1.2 Technical Data of Storage Batteries:....................................................................... 95

2 Battery Operation and Maintenance ...................................................................................... 95 2.1 Operating Mode of DC Systems .............................................................................. 95 2.2 Operating Parameters of DC Systems .................................................................... 96 2.3 Patrol Inspection for DC Systems ........................................................................... 96 2.4 C. How to Operate DC System: .............................................................................. 97

3 Abnormal Operation and Accident Handling for DC Systems ............................................ 98 3.1 Abnormal DC Busbar Voltage................................................................................. 98 3.2 HF Switching Rectifier Failure ............................................................................... 98 3.3 DC Systems are Grounded ...................................................................................... 99 3.4 Treatment for other Failures ................................................................................... 99

4 Emergency Power Supply ...................................................................................................... 100 4.1 Technical Data of Diesel-engine Generator .......................................................... 100 4.2 Patrol Inspection for Diesel-engine Generators ................................................... 100 4.3 Main Steps for Routine Diesel generating set test ............................................... 101 4.4 Start and Stop Mode of Diesel Generating Sets ................................................... 101 4.5 Main Steps for Returning Diesel Generating Set to Standby State .................... 102 4.6 Main steps for parallel operation with the protective section after the

diesel-engine generator has been manually started ............................................. 102 5 AC UPS System ...................................................................................................................... 103

5.1 Main Technical Data of the UPS ........................................................................... 103 5.2 Main Characteristics of the UPS ........................................................................... 104 5.3 Startup ..................................................................................................................... 110 5.4 Shutdown ................................................................................................................ 111 5.5 Load Changeover to Service Bypass ..................................................................... 112 5.6 Change over the load from service bypass to inverters ............................................. 112


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5.7 Operating mode:............................................................................................................ 113 6 Operating environment of UPS: ............................................................................................. 114

Chapter VII Protection and Automatic Device.................................................................................... 115 1 General Provisions on Protections and Automatic Devices .................................................. 115 2 Patrol Inspection on Protections and Automatic Devices ..................................................... 116 3 Generator –Transformer Unit Protection ............................................................................ 116

3.1 Brief introduction ................................................................................................... 116 3.2 Protective Functions of RCS-985A ....................................................................... 117 3.3 Generator –transformer Unit Protection Configuration .................................... 119

4 Microprocessor-based Generator Synchronizer .................................................................... 121 5 150kV Circuit-breaker Protection ........................................................................................ 122

5.1 150kV Circuit-breaker Protective Functions ....................................................... 122 5.2 Technical Requirements for Automatic Reclosing ............................................... 123 5.3 Circuit-breaker Failure Protection ....................................................................... 125 5.4 Three-phase Discrepancy ....................................................................................... 125 5.5 RCS-922A Stub Protection .................................................................................... 125 5.6 Circuit-breaker Operator Box .............................................................................. 126

6 150kV Line Protection ............................................................................................................. 126 6.1 RCS-902A Digital Rapid Ultra HV Line Protective Device (for 150kV Line) .. 126 6.2 SRCS-9611C Line measuring and Protective Device ................................................. 127

7. 150kV System Busbar Protection .......................................................................................... 128 7.1 Protection Configurations ............................................................................................ 128 7.2 Performance Characteristics ........................................................................................ 128 7.3 Differential Busbar Protection ..................................................................................... 129 7.4 Circuit-breaker Failure Protection .............................................................................. 129 7.5 Check for Broken AC Current Circuits ...................................................................... 129 7.6 Device Operation Description ...................................................................................... 129

8. Computer-based Step-up Substation Supervisory Control System .................................... 133 8.1 Functions of Computer-based step-up Substation Supervisory Control System ..... 133 8.2 Main Features of NCS300UX Supervisory Control System ...................................... 133 8.3 NSC300UX Architecture ............................................................................................... 133

8.3.1 System Structure ................................................................................................ 133 8.3.2 Main functions of computer-based supervisory control system:.................... 134

9. Startup/backup Transformer Protection ............................................................................... 134 9.1 Protective functions of 1RCS-985T.............................................................................. 135 9.2 Other functions .............................................................................................................. 135

10 Rapid Auxiliary Power Change-over Device ....................................................................... 135 10.1 Main Features of the Device ....................................................................................... 135 10.2 Device Software ........................................................................................................... 136 10.3 Main Technical Specification...................................................................................... 136 10.4 Monitoring and Display function ............................................................................... 136 10.5 Changeover function ................................................................................................... 137 10.6 Load Reduction in case of Low Voltage..................................................................... 138 10.7 Alarm block and failure processing function ............................................................ 138 10.8 Abnormal Circuit-breaker Positions (Position Blocking/Decoupling).................... 140 10.9 Device Self-test Failure ............................................................................................... 140


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10.11 PT Breakage ............................................................................................................... 140 10.12 Standby Power Failure Monitoring ......................................................................... 140 10.13 Unblocking ................................................................................................................. 140 10.14 Protection Speedup Functions .................................................................................. 141 10.15 Daily Maintenance .................................................................................................... 141 10.16 Failure Analysis ......................................................................................................... 141 10.17 Selection of 6kV Auxiliary Power Supply System Changeover Mode for #31, #32

and #33 Units .......................................................................................................... 142 11 6kV Auxiliary Power Supply System Protection and Automatic Device ........................... 142

11.1 Application of Series WDZ4OO Microprocessor-based protection in the plant .................................................................................................................................. 142

11.2 WDZ-430EX Motor Protection and Control Device ................................................ 143 11.3 WDZ-431 EX Motor Differential Protection ............................................................. 144 11.4 WDZ-410EX Line Protection and Control Device ................................................... 145 11.5 WDZ-440EX Transformer Protection and Control Device ..................................... 145

12 380V Auxiliary Power Supply System Protection and Control Device .............................. 146 12.1 Smart Controller .................................................................................................. 146 12.2 Smart MCC Control12.2.1 Device and Protection ........................................... 147 13.1 Scope ............................................................................................................................. 148 13.2 Typical Operation ................................................................................................... 148 13.3 DCS System Failure ............................................................................................... 150


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Chapter I Primary Wiring System 1 Electrical Primary Wiring 1.1 Main Electrical Primary Wiring

1.1.1 150kV Step-up Station

The connection mode of 150kV system is a typical 3/2 connection mode to be composed of 4 circuits of 3/2 circuit breaker connection, in which there are 3×315MW generator units, a set of startup standby transformer and 4 transmission lines to be separately connected.

BANTEN 3×315MW CFSPP

BANTEN 3×315MW CFSPP Station

The main connection adopts 3/2 connection with 4 equipment circuits and 2 protection compartments. The equipments in this phase of project are composed of 12 circuit breakers, 32 groups of isolating switches, 34 groups of earthing switches and 8 groups of fault closing earthing switches.

1.1.2 Connection of Generator-Transformer Unit

The generator-transformer unit adopts a unit connection of isolated phase enclosed busbar.

The neutral points of the high voltage sides of three main transformers are directly earthed.

Voltage transformers, lightning arresters and an excitation transformer are connected in parallel at the generator outlet.

The neutral point of generator is earthed via a high impendence transformer.

Two sets of lightning arresters and voltage transformers are connected in parallel at the high voltage side of the generator-transformer unit, one group of double-column outlet isolating switch (double earthings) is installed, and two sets of earthing switches are set at both sides of it.

1.2 Auxiliary Power Connection

1.2.1 6kV Auxiliary Power System

Three high voltage auxiliary power transformers are split-winding transformers in which the neutral point is earthed via a high resistance.

A standby auxiliary power supply is fed from 150kV system; one group of double-column outlet isolating switch is installed at the high voltage (HV) side of startup standby transformer, and two sets of earthing switches are set at both sides of it; the neutral point at the HV side of startup standby transformer is directly earthed via a knife-switch; the neutral point at the low voltage (LV) side is earthed via earthing resistance cabinet.

The LV side of startup standby transformer is connected with the LV sides of three HV auxiliary power transformers in parallel, and separately connected to the section A and B of 6kV auxiliary power.

Each unit is equipped with two sections of 6kV auxiliary power working busbars (separately section 10BBA/10BBB, section 20BBA/20BBB and section 30BBA/30BBB), and all 6kV auxiliary equipments of steam turbine and boiler are separately connected to the two sections of auxiliary power working busbars.

6kV auxiliary power system is equipped with special common busbar sections; common loads are respectively connected to 6kV common busbar section 00BBA and 00BBB which are separately fed from sections 10BBB and 20BBB, and a busbar tie switch 00BBB02 is installed between the two common busbar sections.

1.2.2 400V Auxiliary Power System

LV auxiliary power system adopts a neutral point direct earthing mode.


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380/220 LV auxiliary power system of main building adopts power supply modes of power center (PC) and motor control center (MCC). All LV transformers are separately configured in couples on the basis of classifications of unit transformer, electrostatic precipitation transformer and common transformer so as to achieve “physical distribution” and save cables in the main building.

Each unit is equipped with two unit transformers with 2000KVA capacity in mutual standby and two electrostatic precipitation transformers with 2000KVA capacity in mutual standby.

Three units are equipped with two 400V common busbar sections; the loads of main building and LV common loads nearby are connected to the common busbar sections, which are separately fed from two LV common transformers with 2500KVA capacity in mutual standby.

Each unit is equipped with a lighting transformer with 400KVA capacity, which is used as the normal lighting power supply in the main building and nearby areas. One standby lighting transformer is connected to 6KV common busbar section to use as a standby power supply of 380V lighting busbar sections for all units.

Each boiler is equipped with two electrostatic precipitation transformers with 2500KVA capacity in mutual standby.

Two LV auxiliary power transformers with 1600KVA capacity in mutual standby are installed for water treatment and service water.

The circulation water system is equipped with two LV auxiliary power transformers with 630KVA capacity in mutual standby.

A comprehensive coal conveying building is equipped with two LV auxiliary power transformers with 800KVA capacity in mutual standby.

1.2.3 Emergency Power Supply

Each unit is equipped with two sections of emergency power supply busbars with a busbar tie switch installed between them to supply to all AC emergency loads of this turbine and boiler.

The capacity of each diesel generator selected is: 720KW, and there are 3 diesel generators which are used as standby power supplies of emergency power supply.

2 Operation Modes of Systems 2.1 150KV System

A typical 3/2 circuit breaker connection mode is used for 150KV step-up station system. Three generator-transformer units, a startup standby transformer and four outgoing lines are put into operation and four 150kV series circuits are operating in closed loop under a normal condition. The operation mode will be executed in special period in accordance with equipment overhaul condition and commands of dispatchers.

There must be two series and above of circuit breakers to be operated in parallel in a special mode when 150kV double busbars are operating.

The 150kV system must not be operating without busbar.

The standard frequency of 150kV system is 50Hz, and the deviation must not exceed ±0.2Hz. The system frequency is controlled in 50±0.2Hz in normal condition, the operator who is responsible for monitoring panels should monitor the system frequency and report to the dispatcher on duty when abnormal frequency occurs.

The voltage of 150kV system should be monitored and adjusted in accordance with the voltage curve specified by the dispatching agency, and it should be reported to the dispatchers on duty when the operation voltage exceeds the specified scope of voltage curve and can not be adjusted.

When power cut operations for overhaul are to be carried out, at first, the primary equipment should be manipulated, and then, the relay protections should be stopped, the control power


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supply switch should be switch off, and finally, the earthing knife-switch should be closed (or earth wires are installed). When power on operations are to be carried out, at first, the earthing knife-switch should be opened (or the earth wires are removed), and then the relay protections are put into operation and the control power supply switch should be closed, and finally, the primary equipment should be operated.

The actual current in each part of GIS must not be permitted exceeding the rated operating current.

Circuit breakers, knife-switches and earthing knife-switches are prohibited to put into operation before SF6 pressures have not reached the normal pressure value.

When there is SF6 leakage with GIS, the site inspection should be at least carried out by two persons who wear oxygen mask. It should be checked fans are in normal operation before entering into the site; if the fans are not put into operation, entry can not be permitted until the fans are put into operation.

If it is found that the operating mechanism is blocked, knife switch and earthing knife switch do not act, the operation should be stopped immediately when the 150kV knife switch and earthing knife switch is manipulated in remote or in local. The operation can continues after the reasons are found out and the fault has been eliminated.

After an operation of any 150kV circuit breaker, knife-switch or earthing knife-switch is completed, the operation condition of the device should be inspected, and the next operation can be carried out after it is ensured that three phases have been closed or opened.

As for normal power on and off operation of busbar, a circuit breaker must be used for busbar charging or power cut, and all protections of this busbar should be put into operation before the busbar charging.

In case a busbar is to power cut for overhaul, all circuit breakers in the side of the busbar and knife-switches in both sides of the circuit breakers must be opened, the PT secondary switch of this busbar shall be opened, and the earthing knife-switch shall be closed.

When 150kV incoming and outgoing lines are to be switched from the operation state to the hot standby state, the middle circuit breaker should be opened at first, and then the circuit breaker in the side of busbar should be opened; when 150kV incoming and outgoing lines are to be switched from the hot standby state to the operation state, the circuit breaker in the side of busbar shall be closed at first, then the middle circuit breaker shall be closed.

When a circuit breaker is to be switched from the hot standby state to the cold standby state, the knife-switch in the load side shall be opened at first, and then the knife-switch in the power side shall be opened; when a circuit breaker is to be switched from the cold standby state to the hot standby state, the knife-switch in the power side shall be closed at first, and then the knife-switch in the load side shall be closed.

When a 150kV outgoing line is to be switched from the hot standby state to the overhaul, the line knife-switch should be opened at first, and then the earthing knife-switch in the line side shall be closed after it is confirmed that there is no voltage on the line in accordance with the commands of dispatchers.

When a 150kV outgoing line is to be switched from overhaul state to hot standby state, the earthing knife-switch in the line side should be opened, protections for this line shall be put into operation, the circuit breaker of the line shall be opened, and the knife-switch of the line shall be closed in accordance with the commands of dispatchers.

When a busbar voltage failure occurs, it should be immediately reported to the dispatcher on duty, and at the same time, all circuit breakers in the busbar side should be switched off.

It is strictly prohibited to unlock the lock devices of circuit breakers, knife-switches and earthing knife-switches without authorization for forcedly operating the circuit breakers, knife-switches


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and earthing knife-switches.

2.2 Auxiliary Power System

Auxiliary power busbar section 6kV10BBA & B/20BBA & B/30BBA & B are separately fed from HV auxiliary power transformer 1, 2 and 3 in the normal operation mode. The startup standby transformer 30 is used as an interlock standby of busbar section 6KV10BB A, B/20BB A, B/30BB A, B by a quick switchover device.

In the normal operation mode, 6kV common busbar section A is fed from busbar section 6Kv10BBB via switch 10BBB05 and 00BBA01 in series; 6kV common busbar section B is fed from busbar section 6KV20BBB via switch 20BBB05 and 00BBB01 in series; 6kV common busbar section A and B is equipped with a busbar tie switch 00BBB02 which can be switched over in normal condition or in emergency condition by a quick switchover device.

In the normal operation mode, 6kV common busbar section A is fed from busbar section 6kV31B via switch 6205 and 6001 in series; 6kV common busbar section B is fed from busbar section 6kV32B via switch 6206 and 6002 in series; 6kV common busbar section A and B is equipped with a busbar tie switch which can be switched over in normal condition or in emergency condition by a quick switchover device.

In the normal operation mode, each busbar section of 400V auxiliary power is separately fed from respective LV working transformer. Other busbar sections are divided into two sections of A and B which are mutual standby; the standby lighting transformer provides a standby power supply of the lighting busbar section.

All combined switches of MCC local power supply are in working positions. All MCC power switches fed from PC busbar section are closed, and the working power supply in the MCC side is switched on, a standby power supply is in interlock standby by ATS (automatic transfer switching equipment).

In a normal condition, the operation mode of auxiliary power must not be arbitrarily changed without consent of the shift supervisor; it should be immediately reported to the shift supervisor after the operation mode of auxiliary power is changed under an emergency condition or accident treatment.

In a normal condition, the HV auxiliary power transformer and the startup standby transformer, and two LV transformers in mutual standby must not operate in parallel, but short time parallel operation is permitted during switchover.

Two power supplies for each motor control center (MCC) and I&C distribution box must not operate in parallel, but short time parallel operation is permitted during switchover.

2.3 Emergency Power Supply In normal condition, each standby power switch of emergency power busbar section in the distribution board of diesel generator is in interlock standby.

In normal condition, the working power supply of emergency power busbar section of the unit is put into operation, and the busbar tie switch is in interlock standby.

The diesel generator will automatically start up after the unit busbar voltage is lower than the setting value; it will be put into operation within 15s and carry 100% load.

In case the emergency power busbar section needs to switch to the working power supply when the diesel generator operates to supply power to the emergency power busbar section, the interlock of this section should be out of operation at first, and the standby switch should be opened, and then the working power switch is closed, finally the diesel generator is switched over standby state. (Instantaneous voltage loss of the emergency power busbar section will occur during the switchover; therefore, some relevant measures should be taken to ensure the safety operation of the unit.)


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Chapter II Generator 1 Equipment Specifications 1.1 Generator Nameplate Parameters

Steam Turbine Generator Model QFSN-300-2-20B Standard number of

product GB/T7064

Rated capacity 371.7MVA Insulation class F Rated power 316 MW Rated working

hydrogen pressure 0.3 MPa

Rated stator voltage

20 kV Maximum working hydrogen pressure

0.35 MPa

Rated stator current

10732 A Wiring mode 2—Y

Rated power factor

0.85（lag） Cooling water flow rate of stator winding

45m3/h

Rated frequency 50 Hz Cooling water pressure of stator winding

0.1-0.2 MPa

Rated rotary speed 3000 r/min Rated excitation current

2153A

Manufacturer Dongfang Electric Machinery Company Limited Introduction of Generator Model:

This generator is model QFSN-300-2-20B steam turbine generator unit of Dongfang Electric Machinery Plant. It is a three-phase two-stage non salient pole rotor synchronous generator which is directly driven by steam turbine. In which Q-denotes it is driven by steam turbine; F-denotes generator; S-denotes the stator winding of generator adopts water cooling; N-denotes the rotor winding of generator is internal hydrogen cooling; 300-denotes the rated capacity of generator is 300MW; 2-denotes the magnetic poles of generator are two poles; 20-denotes the rated voltage of generator is 20kV; B-denotes tag number.

1.2 Design Specification of Generator

1.2.1 Main Design Parameters of Steam Turbine Generator

Rated power: 316MW Rated apparent power: 371.7MVA

Rated voltage: 20kV Rated current: 10.732kA

Rated power factor: 0.85 Rated frequency: 50Hz

Rated exciting voltage: 472V Rated excitation current: 2153A

Rated rotary speed: 3000rpm Numbers of phases: 3 phases

Connecting way: 2—ㄚ Numbers of outgoing Terminals：6

Short circuit ratio: 0.5929 Efficiency: 98.9％

Each phase DC resistance of stator: 0.001658Ω

Rotor winding DC resistance: 0.162766Ω

No.load excitation voltage: 151.4V

No.load excitation current: 824.23A


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Short-circuit excitation current: 1390.07A

Insulation class: F (examine as per Class B)

1.2.2 Technical Parameters of Hydrogen in Generator Stator Housing

Rated gauge pressure: 0.30±0.02MPa Maximum gauge pressure: 0.35 MPa

Hydrogen purity: ≥95％ Humidity under rated conditions:≤4g/m3

Cold hydrogen temperature: 30 to 45℃ Hot hydrogen temperature: ＜70℃

Hydrogen leakage in 24 hours:＜12 m3 Hydrogen volume in generator: 72 m3

1.2.3 Technical Parameters of Stator Cooling Water

Water inlet temperature:45±3℃ Water outlet temperature:≤90℃

Water flow rate: 45t/h Water inlet pressure: 0.1～0.2 MPa

pH value: 6.5～8 Hardness:≤2μg/L

Conductivity (20℃):≤0.5 to 1.5μs/cm

1.2.4 Technical Parameters of Cooling Water for Hydrogen Cooler

Number of hydrogen coolers: 4 Water inlet temperature: 20 to 30℃

Water outlet temperature:≤45℃ Water flow rate: 4×100t/h

Water inlet pressure: 0.1 to 0.2 MPa

1.2.5 Technical Parameters of Bearing Lube oil and Sealing Oil

Bearing oil inlet pressure: 0.05 to 0.1 MPa Sealing oil differential pressure between air side and hydrogen side: 0.005 MPa

Oil inlet temperature: 35 to 45℃ Oil outlet temperature:≤70℃

Sealing oil pressure is higher than hydrogen pressure by: 0.08 to 0.10 MPa

1.2.6 Generator Temperature Limit Parameters

Outlet water temperature of stator winding and outgoing terminal: ≤85℃

Temperature among layers of stator winding: ≤90℃

Temperature difference between layers of stator winding: ≤15℃

Temperature of structural members on stator end: ≤120℃

Rotor winding temperature: ≤120℃ Bearing bush temperature:≤90℃

1.3 Technical Characteristics of Generator

Cooling mode: water-hydrogen- hydrogen

Ventilation mode: A closed circulation multi-channel ventilation system with axial fans on both ends is adopted in generator; the hydrogen in generator is cooled in the hydrogen cooler where water flows by; Slip ring adopts open type pipe ventilation.

Water supply mode of stator winding: The cooling water of stator winding is supplied by the cooling water tank of generator stator.

Hydrogen (oil) sealing mode: Single- ring type oil sealing is adopted.


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Oil supply mode: The bearing lube oil is supplied by the lube oil system of steam turbine; the sealing oil of oil sealing is supplied by an external sealing oil system.

Excitation mode: A self and shunt excitation system with GES-3320 synchronous generator terminal transformer static rectification is adopted.

Insulation class: Insulation class F is used for stator winding and stator iron core (It is used as per class B)

1.4 Basic Technical Requirements

1.4.1 Ambient Temperature

The environmental condition of continuous operation for generator and auxiliary equipments (ambient temperature in main building) is 5 to 45℃.

1.4.2 Resistance Value Deviation of Stator Winding

After excluding the error caused by difference of lead wire lengths, the difference between the measured values of cold state resistances in any two phases is not more than 1.0% of the minimum.

1.4.3 Insulation Resistance

a） The stator winding insulation resistance measured by 2500V megger is not less than 5MΩ in dry state at approximate working temperature.

b） The rotor winding insulation resistance measured by 500V megger is not less than 1MΩ at room temperature (20℃).

c） The insulation resistance of temperature measuring element measured by 250V megger is not less than 1MΩ at room temperature (20℃).

d） The insulation resistance of excitatory side bearing and oil seal against ground measured by 1000V megger is not less than 1MΩ.

1.5 Structure of Generator Body

1.5.1 Stator Winding

The stator winding is double-layer basket structure formed by single-turn winding, adopts continuous type class F epoxy powder mica insulation system and is provided with corona proof measures on surface, and is provided with favorable insulating property and mechanical property.

The winding coil is cooled by water, water tie-ins are welded on both ends of bar and insulated diversion pipes are connected to water inlet and outlet headers. Hollow lead and solid lead form double-row leads in a specified proportion, in this way, a favorable cooling effect and higher availability ratio of slots can be achieved, and 540°transposition of coil is carried out in the slot portion to reduce the circulating current loss.

1.5.2 Stator Iron Core

The stator iron core is assembled by the lamination of sector silicon steel sheets to be insulated (staggered lamination is used). The silicon steel sheets selected are provided with lower loss and good magnetic conductivity. Class F insulation paint added with inorganic filling is applied as inter-sheet insulation after punching of the silicon steel sheets and burrs removing.

1.5.3 Generator Stand

Generator stand is a shell structure welded by steel plates and is provided with enough intensity and rigidity. Its functions are to support stator iron core and stator winding, and form special cooling air flow channel. Acting as an enclosed container of hydrogen, it can endure impacts generated by accidental hydrogen explosion.

The stand is composed of end plate, sheath and air zone baffle plates etc which are assembled and


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welded together to form special inlet air zone and outlet air zone. The stand is designed to three sections, i.e. one intermediate section and two end shields.

The stand and the end shields have respectively undergone a hydraulic pressure test with 1.0MPa for 30 minutes and an airtight test with 0.4MPa for 24 hours. The junction planes between the end shields and the stand and between the end shields and the outgoing line are sealed by welding. A method of inserting rubber strips into dovetail slot and applying sealant is used for sealing between the end shields and the end covers.

A number of temperature measuring terminal blocks are laid in the lateral surface of end shields; and lead wires of temperature measuring elements in the generator are led out by the temperature measuring terminal blocks.

Flanges are used for connecting all external oil, water and air pipes to the generator.

1.5.4 Outgoing Line Terminal (Outgoing Line Bushing)

Six outgoing line terminals (three ones are neutral points, and three ones are output ends of electric power) are led out from the nonmagnetic steel outgoing line shield in the lower part of exciter end shield. The outgoing line terminal is composed of HV porcelain insulator and hollow conductive bar in which cooling water flows through.

1.5.5 Generator Ventilation

The stator iron core and the rotor winding are cooled by hydrogen enclosed circulation system. The hydrogen is driven by single stage axial fans on two ends of rotor.

The hydrogen stream from the axial fan enters into respective cold air zone by guide duct in the generator stand, and enters into the air gap from the iron core back along the iron core radial channel, and then it enters into channel of rotor winding to cool the rotor winding, afterwards, the hydrogen stream returns to the air gap and enters into the hot air zone along iron core radial channel, and flows through the cooler installed on the upper part of end shield via guide duct, and then it return to the axial fan again to continuously circulate.

Quantity are equal and positions are coincident for air zones of stator and rotor; the cold air zones and the hot air zones are alternately laid along axial direction, this kind of layout makes the stator and the rotor to cool evenly and the temperature to be more uniform.

1.5.6 Temperature Detector

Resistance temperature detectors (RTD) and thermometers shall be installed in the following positions:

Water outlet end of each water circuit of stator winding coil and outgoing line (RTD);

Between the upper layer coil and the lower layer coil of each stator slot (RTD);

Tooth portions and yoke portions of stator iron core (not less than 12 RTD);

Cold air side and hot air side of cooler (RTD and thermometer);

Bearing bush (RTD);

Bearing oil outlet pipe (RTD and thermometer);

Oil sealing oil outlet pipe (RTD);

Main water inlet pipe and each water outlet pipe of hydrogen cooler (RTD and thermometer);

Slip ring outlet air (thermometer);

Temperature elements are 100ω（0℃）platinum thermal resistance (double elements).

Lead wires of all temperature elements in the generator stand are shielded wires.

Thermocouples are laid in clamping finger, clamping ring and copper shielding on stator end.

All temperature limit values shall conform to the stipulations in national standard GB/T7046


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when the generator is operating with specified cooling medium in the rated conditions.

1.5.7 Rotor Shaft

Rotor shaft is manufactured by integral high strength and high magnetic conductivity alloy steel. There are axial slots machined on the rotor body to place excitation winding, at the same time, the rotor body acts as magnetic circuit. Rotor is provided with transfer function, and endures torques in accidental state and huge centrifugal actions generated by high speed rotation.

Transversal slots machined on the rotor gear wheel are used for equalizing the rigidities in gear wheel and pinion direction to avoid multiple-frequency vibration resulting from a bigger rigidity difference between the gear wheel and the pinion.

1.5.8 Rotor Winding

Rotor winding is made of silver-bearing copper wire with favorable electric conductive performance, mechanical property and creep resisting performance. The slot portion of rotor winding adopts a gap-pickup diagonal flow internal cooling mode, and the end part adopts two-way ventilation cooling mode. When the rotor is rotating at high speed, the cold hydrogen in the gap enters into winding diagonal channel from slot wedge windward scoop in inlet air zone (The winding channel is formed by hole machined on the copper wire), and reaches the bottom of slot, afterwards, it returns to the gap outlet air zone along another diagonal channel and carry away copper wire loss. In this way, the rotor rotation generates air pressure to form “self ventilation system”.

1.5.9 Generator retaining rings are made of non-magnetic high strength alloy steel forging, are provided with a suspension type structure, and shrink on the two ends of rotor body. They are used for protecting rotor end winding to prevent it flying apart due to centrifugal force.

The retaining rings on the two ends of rotor are equipped with damping rings which are made of copper plate, and positioned on the tooth portion and goes into below the body slot wedge. The damping rings improve the capability of bearing negative sequence load.

1.5.10 Generator slip ring is made of wear resistant alloy steel and is installed on the rotor by shrinking. There is an insulating sleeve between the slip ring and rotor shaft. The slip ring and carbon brush device can enhance the rated output of generator and excitation current required by reinforced excitation.

There are axial and radial air holes on the slip rings. The spiral flute on the surface can improve the contact condition between the electric brushes and the slip rings to make current distribution to be even between the electric brushes. The slip rings are connected to the rotor winding by means of conductive screws and rotor lead wires. The conductive screws are made of chromium copper alloy and are provided with high strength and high conductivity. There is seal structure between the conductive screws and rotor shaft to prevent hydrogen leakage. There are coaxial centrifugal fans between two slip rings to forcedly cool the slip rings and the electric brushes.

1.5.11 The hydrogen in the generator stand is sealed by pressure oil between the rotor shaft and sealing pad. The sealing oil pressure should higher than hydrogen pressure by 0.05MPa. The sealing system is single-ring type. The sealing pad located in the sealing socket is split into two halves in the axial and radial direction which are connected by spring and be provided with good follow-up performance.

1.5.12 The generator uses horizontal split elliptical bearing. The mating surface of bearing and bearing seat is spherical surface. The excitation bearing is equipped with insulation against ground to prevent bearing journal and bearing alloy to be burned by shaft current. The bearing is installed on the end cap. The end cap is made of steel plate by welding.

1.6 Cooling System of Generator

The cooling capacity of generator will affect the generator output to a certain extent, and the cooling effect of generator will directly affect the load carrying capacity of generator,


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consequently it must adequately attach importance to the cooling system of generator.

This steam turbine generator adopts a “water-hydrogen-hydrogen” cooling mode, i.e. the stator windings (including stator winding coil lead wire, stator transition lead wire and outgoing line) adopt internal water cooling; the rotor windings adopt internal hydrogen cooling; the stator iron core and end structures adopt hydrogen surface cooling. The slip rings adopt air cooling.

The hydrogen in the generator stand is driven by axial fans installed on the two ends of rotor, and carries out enclosed circulation.

The cooling system of this generator is mainly composed of three auxiliary systems of “hydrogen, oil and water”, i.e. hydrogen control system, sealing oil system and stator coil cooling water system.

1.6.1 Hydrogen System

The hydrogen control system is to use for displacing the gas in the generator, to feed hydrogen into the generator in control, to keep the stabilization of hydrogen pressure in the generator, to monitor the hydrogen purity and leakage of liquid and to dry the hydrogen in the generator.

The hydrogen system is equipped with a series of alarm switches which carry out controls and alarms to hydrogen purity, pressure, temperature, hydrogen supply pressure and leakage of generator.

Main technical parameters:

a） Inside generator shell

Rated hydrogen pressure: 0.25MPa (gauge pressure, the same below)

Hydrogen purity: >96% (volume ratio)

Hydrogen humidity: ≤4g/m3 (0.25MPa under the condition of hydrogen pressure)

b） Hydrogen filling volume of generator and hydrogen pipeline 71 m3

c） Hydrogen leakage of generator and hydrogen pipeline system (excluding storage equipment and hydrogen main pipe) 5% hydrogen filling volume

d） Cooling water of generator hydrogen cooler

Numbers of coolers: 4

Water inlet temperature of hydrogen cooler: 20 to 38℃

Water outlet temperature of hydrogen cooler: ≤43℃

Water flow rate: 4×100t/h

Water Inlet pressure: 0.1～0.2MPa

Water pressure drop: 0.042MPa

Drag pressure drop of hydrogen cooler: 0.222MPa

e） Cold hydrogen temperature: 35 to 46℃

1.6.2 Sealing Oil System

The oil (in fact it is steam turbine bearing lube oil) needed by the sealing pad of generator is customarily referred to as sealing oil according to the usage. The sealing oil system is exclusively used for supplying oil to the generator sealing pad, and the oil pressure is higher than the hydrogen pressure in the generator for a certain value to prevent the hydrogen leakage from the gap between rotor shaft and sealing pad, meanwhile, prevent outrgeous oil pressure resulting in large amounts of oil feed in the generator.

This generator adopts double-flow ring type sealing pad (two lines of the oil at the hydrogen side


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and air side. The oil quantity, temperature and pressure are ensured by the external sealing oil system.


Item parameter Value Rated differential pressure between the sealing oil pressure and the hydrogen pressure

0.085±0.01Mpa

Total oil quantity of the sealing pad at the air side 198L/min Total oil quantity of the sealing pad at the hydrogen side 110L/min Feeding temperature of the sealing oil ≤520C Discharge temperature of the sealing oil (air side) ≤560C Discharge temperature of the sealing oil (hydrogen side) ≤650C Operating temperature 0．3MPa Feeding temperature of the secondary cooling water ≤330C Hydrogen purity ﹥98%

1.6.3 Stator Cooling Water System

The stator cooling water system is used for ensuring water supply to the stator coil uninterruptedly and monitoring parameters such as water pressure, flow rate and conductivity. The system is equipped with an automatic water temperature regulator to regulate the water inlet temperature of stator cooling water to sustain stabilization on the whole. Meanwhile, an ion exchanger is installed to improve the quality of stator cooling water.


Water inlet pressure: 0.1 to 0.25MPa

Water inlet temperature: 45±3℃

Backwater temperature: ≤85℃

Water flow rate: 45m3/h (including water flow rate of end incoming line and outgoing line 5m3/h)

Water filling volume of the system: 3m3/h

Demanded circulation water flow rate: ～160m3/h

Demanded circulation water pressure: 0.35MPa

Requirements of water quality:

Conductivity: 0.5 to 1.5μs/cm（20℃）

Ph value: 7 to 8

Hardness: less than or equal to 2 microgram equivalent per liter

1.7 Generator Excitation System

This generator adopts type GES3320-T42F20L self and shunt static silicon controlled rectifier excitation system of Dongfang Electric Machinery Control Equipment Co., Ltd. This excitation system is mainly composed of excitation transformer, regulator, rectifier and magnetic blow-out switch etc.

1.7.1 Product Model of Excitation Device


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1.7.2 Application Environment of Excitation Device

Ambient temperature

The maximum ambient temperature does not exceed +40℃. The minimum ambient temperature is not lower than -10℃ when the air cooling device is used, and the cooling water temperature is not lower than +5℃ when the water cooling device is used.

Relative humidity of environmental air

The monthly average maximum relative humidity is less than 90% in the operation location in the moistest month, meanwhile, the monthly average minimum temperature in this month is not higher than +25℃.

The altitude does not excess 1000m.

Gas pollution

There is no conductive or explosive dust in the operation location. There is no corrosive metal or gas or vapor damaging insulation. There should be dust proof and ventilation measures in the installation site.

Vibration

The vibration conditions in the installation site: the vibration acceleration is not more than 5m/s2 when the severity level of vibration frequency is 10 to 150Hz.

1.7.3 Basic Performance Indexes

The excitation system can continuously operate when the exciting voltage and excitation current of synchronous generator do not excess the 1.1 times of the rated exciting voltage and current.

The times of ceiling voltage of excitation system (i.e. times of reinforced excitation voltage) is not less than 1.8 times.

The time of reinforced excitation permitted by the excitation system is no less than 10s.

The nominal response of excitation system is not lower than 2 times/s.

Regulating scope of automatic exciting regulator:

1)When the generator is in no-load condition, it can ensure stable and smooth regulation within the scope of rated no-load voltage 30% to 110% of generator;

2）When the generator is in synchronization, it can ensure stable and smooth regulation within the scope of rated no-load voltage 90% to 110% of generator.

Under the no-load operation condition, the change speed of specified voltage of excitation


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regulator is not more than 1% of rated voltage of generator per second, and not more than 0.3% of rated voltage of generator per second.

The setting range of generator terminal voltage adjustment ratio (reactive current compensation rate) is 0 to ±15％.

The excitation system guarantees the generator static voltage error to be ±1％.

The change rate of generator terminal voltage is not more than ±0.25％ when the frequency changes 1% under the condition of generator no-load operation.

The overshoot of generator voltage is not more than 50% of step quantity, the times of swings do not excess 3 times and the regulating time does not excess 5s when the specified voltage step is ±10％ under the condition of generator no-load operation.

The automatic exciting regulator guarantees the overshoot of generator terminal voltage does not excess 15% of the rated value, the times of wings do not excess 3 times and the regulating time does not more than 10s when the generator suddenly increases voltage from zero.

The maximum instantaneous value of rectified voltage on the two ends of field winding is not more than 30% of voltage amplitude of field winding in the routine test when the field current is less than 1.1 times of rated value. The current stabilizing factor of silicon controlled rectifying bridge is not lower than 0.85 and the voltage balance factor is 0.9 when there are parallel branches and connections in series.

1.7.4 Signal and Power Supply

1) Input signal

The electrical input signals of excitation device derive from voltage transformer and current transformer, and the specification parameters are:

Voltage 3×100V 50Hz three phases

Current 3×5A 50Hz three phases

2)Conditions of working power supply

The permissible deviation of AC voltage is -15% to +10% of rated value, and the permissible deviation of frequency is -6% to +4% of rated value.

The permissible deviation of DC voltage is -20% to +10% of rated value.

1.7.5 Main Equipments of Excitation System

The excitation system utilizes excitation current to regulate generator terminal voltage and reactive power; the excitation current is fed from the silicon controlled rectifying bridge; the automatic exciting regulator controls the output of the silicon controlled rectifying bridge. The excitation transformer provides power source to the excitation system.

1) Excitation transformer

Description Specification and technical parameters Quantity

Excitation transformer 3600KVA，20/0.9KV Ud=8% Yd11 3

The excitation transformer provides power source to the excitation system and electrically separate the excitation equipment and the generator terminal. The HV side of excitation transformer is connected to the generator terminal, and LV side is connected to the AC input side of high power silicon controlled rectifying bridge.

2) Silicon controlled rectifying bridge


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The silicon controlled rectifying bridge rectifies the AC current provided by excitation transformer to DC current to output to the excitation circuit of generator. In general, three groups of bridges work in parallel and share the load. The device satisfies the excitation requirement under the rated operation condition of generator when one group of bridge is out of operation.

The automatic exciting regulator controls the silicon rectifying bridges and regulates the output power of it to change the excitation current of generator, so that the generator terminal voltage and reactive power are regulated.

3) Magnetic blow-out switch

The magnetic blow-out switch is a visible break point between the generator rotor winding and the exciting rectifying bridge. DC output of silicon controlled rectifying bridge is fed to the generator rotor winding by the magnetic blow-out switch.

4) Automatic exciting regulator

The automatic exciting regulator is located in the regulating cabinet, and is divided into several parts of signal processing, control calculating and signal output. It acquires information of various analog quantities and switch quantities of generator, and controls the outputs of silicon controlled rectifying bridges by calculating and processing of industrial computer so as to achieve the control objectives of excitation system.

The automatic rectifying regulator adopts redundancy and fault tolerance structure with double channels. Signal acquisition, input regulation, calculation and signal output are provided with two sets of independent hardware circuits. Two channels are associated as well as independently work. The channels adopt master-slave mode to work in parallel and are mutual hot standby. The channels achieve mutual diagnosis and real time online self diagnosis, mutual follow-up, mutual communication and mutual switchover by means of software. When there is no fault with the two channels and two computers power on, one computer which completes the system initialization earlier is the master and will gain the masterdom of excitation system; another computer is a hot standby of the master, when once it detects main channel to be in malfunction, it will replace the main channel. The switchover from the master to the slave can also be carried out by human -computer interface.

The analog signal input quantities for regulator includes: generator terminal voltage, generator terminal current, system voltage, exciting current and synchronous voltage.

1.7.6 Control Command

1) System putting into operation

(1). Automatic startup: i.e. “Startup” command, the excitation system is automatically put into operation. The regulator orderly executes closing magnetic blow-out switch, starting up cooling fans of excitation cabinet and putting the excitation initiating circuit into operation.

(2). Manual excitation initiating: i.e. “Excitation Initiating” or “Excitation Putting into Operation” command. After the magnetic blow-out switch is closed, if the command is effective, the regulator will put the excitation initiating circuit into operation and the system initiates excitation to specified position.

2) System switch off

“Automatic Shutdown” and “Excitation Switch Out (inversion)” command will make regulator implement the inverting demagnetization program of rectifying bridge.

The inversing demagnetization should be used at a normal demagnetization without tripping the magnetic blow-out switch. The magnetic blow-out switch will trip in accident, and the magnetic field energy will be released by the demagnetization resistance.

3) Operation of magnetic blow-out switch


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It includes “magnetic blow-out switch switch-in” and “magnetic blow-out switch switch-off”.

4) Setup of regulating mode

Four regulating modes can be set up: constant generator terminal voltage (automatic operation state), constant excitation current (manual operation state), constant reactive power (automatic operation state) and constant power factor. The default mode is: constant generator terminal voltage operation mode.

In principle, four operation modes can be switched over during operation; there is no fluctuation of generator terminal voltage and reactive power to occur during switchover. Exceptions are as follows:

(1). If a fault happens when the constant voltage operation mode is used, the constant current operation mode will be automatically switched. It is not permitted to switch to the constant voltage mode and another two modes before the fault is eliminated.

(2). When the generator is operating in no-load state, it is not permitted that the exciting regulator is switched to constant reactive power mode and constant power factor mode; the two modes are effective only after the main circuit breaker of generator is closed.

Note: The constant current regulating mode (manual) only regulates the excitation current, excluding all limitation functions. Therefore, operators should nearly monitor the generator excitation when the regulator is operating in constant current mode (manual). It is not permitted the generator is operating in the constant current regulating mode in long term.

5)“Excitation increase”/ “excitation decrease”

“Excitation increase”/ “excitation decrease” commands increase or decrease the set point of system regulating object.

The increase/decrease excitation command is to artificially change the specified voltage of generator under the constant voltage mode. This operation will change the voltage of generator in no-load condition; this operation will change the reactive power in load condition. When a limitation function acts, the corresponding limitation will make the increase/decrease excitation command to be invalid.

The increase/decrease excitation command is to artificially change the reactive power and the power factor of generator and make them keep the set points under the constant reactive power and constant power factor mode.

The increase/decrease excitation command is to change the specified field current under the constant current mode. This operation will change the generator terminal voltage in no-load condition; this operation will change the reactive power in the load condition. Operations should be careful in the constant current operation mode, the limits of generator and excitation system must not be exceeded, because the limitator will be out of function in the constant current mode.

The increase excitation (decrease excitation) operation will be invalid when the set point reaches the maximum (minimum).

1.7.7 Protection Limitation Function

The excitation system contains several limitation functions in order to achieve reliable operation of excitation system. The purpose of limitator is to make generator operate in a permissible scope to avoid relay protection action resulting in the generator not to be able to operate continuously. This device provides the following protection limitation functions:

1) Excitation initiating failure

After the command of excitation initiating is send, the generator does not successfully build up voltage in 8 seconds, the regulator will judge the excitation initiating failure, and send


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corresponding alarm signals and cut off the power supply of excitation initiating.

2) Inverting failure

After the command of shutdown or excitation switch-out is sent, the generator terminal voltage does not successfully decrease to 15% rated value and below in 10 seconds, the regulator will judge the inverting failure, afterwards the magnetic blow-out switch will automatically trip to demagnetize by means of demagnetization resistance absorbing the magnetic field energy.

3) Overvoltage protection

A rotor overvoltage protection device bridges over the excitation circuit. The core part of this protection device is ZnO nonlinear resistance, once a surge voltage occurs and excesses the setting value, the protection device will act. The responding value of overvoltage is set to 4 to 5 times of rated exciting voltage.

4) Rotor overcurrent limitation

It is used for current limitation and protection of generator excitation circuit. When the excitation current is more than 1.1 times of rated excitation current and less than the reinforced excitation current, the inverse time lag excitation current protection will be started up; when the excitation current equals to the reinforced excitation current, the ceiling excitation current limitation will act and 10s delay (settable) is permissible.

It will judge whether or not an overexcitation occurs and the overexcitation magnitude, if overexcitation occurs, it will decide to take ceiling value limitation or inverse time lag limitation in accordance with the magnitude of overexcitation; if the overexcitation time reaches the setting time, the overexcitation limitation mark will be placed, and the generator excitation current is limited to the rated value.

5) Underexcitation limitation

The limitation curve is decided by five operating points of (P1, Q1), (P2, Q2), (P3, Q3), (P4, Q4) and (P5, Q5). The coordinates of the five operating points are set up in the human-computer interface station. It will calculate and judge whether or not the underexcitation occurs in accordance with the feedback signals. If the underexcitation occurs, the underexcitation limitation mark will be placed and the excitation will be automatically increased.

6) V/Hz limitation

The V/Hz ratio will be calculated in real time. If the V/Hz ratio is more than setting value, the V/Hz limitation control program will be started up so as to decrease the generator terminal voltage and make the V/Hz ratio reach the setting value, at the same time, the V/Hz limitation action mark will be placed.

7) Output power limitation of power cabinet

It will judge whether or not there is any power cabinet out of service and the quantity. If there is any power cabinet out of service, the marks for power cabinets out of service and quantity will be placed, and the power cabinet out of service limitation program will be called to limit the excitation in accordance with the quantity of power cabinets out of service.

8) Stator current limitation

After the generator stator current reaches the limit value specified, if the generator is in lagging phase operation, the excitation will automatically decreased; if the generator is in leading phase operation, the excitation will automatically increased.

9) TV break wire protection

When U1＜0.85U2, the regulator considers the generator terminal TV break wire, and automatically switches to the standby channel to carry out automatic operation; It will switch to


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the constant current operation mode if PT break wire occurs in standby channel.

In which: U1: Generator terminal PT secondary voltage measured by AVR;

U2: Voltage value of comparison signals measured by AVR, it usually comes from synchronous voltage.

10) Pulse loss detection

When the pulse forming circuit board in the industrial computer of main channel loses pulse, another industrial computer will be automatically switched, meanwhile alarm signals will send. When the pulse magnifying circuit board of rectifying cabinet loses pulse, the regulator will send corresponding alarm signals, meanwhile the pulse output of this rectifying cabinet will be locked and this rectifying cabinet will be out of operation.

2 Operation and Maintenance 2.1 Check and Preparation Work before Steam Turbine Generator Startup

2.1.1 Before the excitation initiating after new installation or overhaul of a generator, it should be checked that the test report and the completion notice are complete and qualified; there is no error with startup measures; all maintenance persons are evacuated from the site; the work permits of generator and auxiliary equipments are taken back; all safety measures are removed; whether or not all short circuit wires and earthing cables are completely removed and all standing fences and nameplates are resumed.

2.1.2 All parts conditions should be checked in detail before the generator is started up.

(1). 150kV system has been put into operation; the startup standby transformer, the auxiliary power system and DC system have been put into operation; the diesel generator is in good standby state.

(2). The primary and secondary circuits of generator, main transformer, HV auxiliary power transformer and auxiliary equipments are normal, and are provided with conditions of putting into operation.

(3). All joint faces of generator body and shell are tight; all screws are tightened; there is no short circuit and smudge with generator bearings; the cold and hot hydrogen thermometers on both sides of generator shell are in good condition.

(4). The slip ring surface of generator is clean and smooth without scratch; all carbon brushes are firmly installed; the distance from the lower edge of any carbon brush to the surface of slip ring is 2 to 3mm; the surfaces of carbon brushes and the slip ring contacts well; the effective length of carbon brushes are not less than 5mm, and the spring pressures are normal.

(5). Enclosed busbars of generator, main transformer and HV transformer are complete without foreign matter.

(6). The appearances of generator outlet voltage transformer, arrester and voltage transformer in the low side of HV auxiliary power transformer are complete; there is no damage, crack phenomena with all porcelain insulators; lead wires and earthing cables are connected firmly; primary fuses are in good condition; secondary air switches have been closed, and all primary contact heads contacts well.

(7). Equipments in generator neutral point cabinet are in good condition, the connecting cables of neutral point high impedance transformer are in good condition.

(8). Magnetic blow-out switch, automatic voltage regulating device and rectifying cabinet and fans of generator are in good condition; there is no damage and dropout phenomenon in operation mechanism.

(9). The mechanical part of withdrawable switch in the LV side of HV auxiliary power transformer is normal and the operating part is normal, the connections of operating mechanism are firm,


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and the wirings of control circuits are firm.

(10). Instruments, signal devices, relay protection devices and automatic and remote devices of generator are normal, the protection setting values are correct, all equipment positions in the generator control display are correct, the signal test is satisfactory, and the complete set test of generator is normal.

(11). Main transformer and HV auxiliary power transformer have been checked to be ready for put into operation, the SF6 circuit breaker and isolating switch at outlet of generator-transformer unit are checked in accordance with requirements, and are provided with condition of putting into operation. All earthing knife switches (earthing wires) are in open position in accordance with the requirements.

2.1.3 All parts of generator-transformer unit are measured to be qualified.

(1). The stator winding is dry without residual water; the insulation resistance against ground and between phases should be ≥5MΩ (measured by 2500V megaohmmeter) when it is close to the working temperature.

(2). The cold (20℃) insulation resistance value of rotor winding should be ≥1MΩ (measured by 500V megaohmmeter).

(3). The cold insulation resistance value of each resistance detector should be ≥1MΩ (measured by 250V megaohmmeter).

(4). Insulation resistances of stator collecting pipe and water inlet pipe of stator outgoing line:

When there is no residual water, they are ≥100kΩ (measured by 1000V megaohmmeter).

When water is flowing, they are ≥30kΩ (measured by 1000V megaohmmeter).

(5). Insulation resistance value of inner and outer oil baffle caps of generator exciter side bearing should be ≥1MΩ (measured by 1000V megaohmmeter).

2.1.4 The stator cooling system of generator is put into operation.

2.1.5 The sealing oil system of generator is put into operation.

2.1.6 The hydrogen cooling system of generator is put into operation.

2.1.7 All instrument devices, relay protection devices, automation devices and alarm signal devices of generator are put into operation.

2.1.8 Tests are carried out prior to startup of generator

(1). Protection and alarm signal test.

(2). Closing and opening tests and interlock test of main circuit breaker and magnetic blow-out switch

(3). Interlock test of excitation DC switch.

(4). Big interlock test of turbine, boiler and electrical part.

(5). Interlock test of working power supply and standby power supply of rectifying cabinet fans, and fan interlock tripping rectifying cabinet test.

(6). Switchover test of HV auxiliary power (after parallel operation of generator)

(7). Protection transmission tests should be carried out when there is working in the secondary circuits or protection circuits of generator-transformer unit.

(8). Stator hydraulic pressure and hydrogen seal test should be carried out after overhaul of generator.

(9). No-load test and short circuit test should be carried out after overhaul of generator.

(10). Closing and opening test of main circuit breaker should be carried out after overhaul and minor


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repair of generator.

2.1.9 All connections of electrical part are to be checked; the generator circuit breaker, the magnetic blow-out switch and the withdrawable switch in the LV side of HV auxiliary power transformer are in open position.

The generator-transformer channel is energized.

2.2 Workings after Impulse Starting of Steam Turbine

2.2.1 Live Equipment

Once a generator is turning, even the revolutions are very low, the generator and various devices connected should be considered as carrying voltage, therefore, it is prohibited to carry out any work in its circuit.

2.2.2 Check at Initial Speed

a） Check whether the mechanical connections of generator are firm, confirming whether or not there is any looseness and dropout phenomena.

b） Check whether there is any friction sound and other abnormal phenomena with generator.

2.2.3 Check at half speed

a） Check whether there is any bad contact or bounce phenomena with the slip rings and carbon brushes when the rotary speed of generator reaches a half of rated rotary speed.

b） The operation of generator cooling system is to be checked, and it should be monitored whether or not the operation parameters of cooling medium conform to the requirements of specified values.

c) The temperature value of each measured point for generator is to be checked and the generator temperature rise condition is to be monitored.

d) Check that the connections of electrical primary circuit of generator-transformer unit are in good condition without discharge phenomena.

e) Check that sounds of generator, main transformer, HV auxiliary power transformer and excitation transformer are normal and the cooling devices of transformers are normally operating.

2.3 Operations

2.3.1 Power on Operation of Generator-Transformer Channel

Check that all safety measures are removed for generator-transformer unit channel and all standing fences and nameplates are resumed; the primary wirings and the secondary wirings are in good condition and ready for power on.

Check that the isolating knife switch at the HV side outlet of main transformer is in open position.

It is to be measured that the insulation resistances of generator, main transformer, HV auxiliary transformer and excitation transformer are qualified.

The DC power supply of protection panel A, B and C of generator-transformer unit is switched on, the outlet strap on the protection panel A, B and C are correctly put into operation as specified.

Generator outlet PT is energized, and the air switch in the secondary side is closed.

The earthing knife switch of generator neutral point is switched on.

Exciting regulating system, magnetic blow-out switch, excitation initiating power supply and fans of exciting regulating system are energized.

Cooling devices of main transformer and HV auxiliary transformer are energized and the trial runs of them are normal.


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Working branch incoming line PT of 6KV busbar section A and B are energized.

HV side PT of generator-transformer unit is energized.

2.3.2 Power on Operation of Excitation System

1) The following conditions should be satisfied before excitation initiating:

There is no equipment maintenance to be carried out at the same time;

The control devices get ready;

Generator equipments get ready;

Generator reaches rated rotary speed;

There is no alarm and fault with any device;

Excitation is in cut off position;

Excitation is in remote (control room) operating mode;

Exciting regulator is in the constant voltage or constant current regulating mode;

The set point of exciting regulator is rated value in no-load condition (or lower than rated value in no-load condition); (The operating state of generator is placed in “quasi-synchronization”; (The system pressure signal is reliably switched on).

2) Excitation switch-on

The magnetic blow-out switch is closed;

Excitation initiates, the generator will build up voltage in 5 to 8 seconds.

The generator voltage is regulated by increasing /decreasing excitation operation, and the system is ready to synchronization.

The generator will operate with the power grid system in parallel after synchronization of the power grid system and the generator are achieved.

The reactive power is regulated to the expected value by increasing /decreasing excitation operation.

3) Excitation switch-off

Reactive power is decreased, and active power is decreased, the main oil circuit breaker of generator trips;

The excitation is cut off, and the generator terminal voltage is zero;

The magnetic blow-out switch is opened (if necessary).

2.3.3 Generator synchronization operation

The command of shift supervisor is received: generator synchronization operation

Check that the rotary speed of generator is >3000r/min, the hydrogen pressure is >0.1MPa and the stator cooling water is normal.

Check that the neutral point knife switch of generator has been closed.

Check that the earthing knife switch in the HV side of main transformer is in open position.

Check that the earthing knife switch of generator-transformer unit is in open position.

Check that the protections of generator-transformer unit is put into operation as required.

The isolating knife switch at the HV side outlet of main transformer is closed.

Check that the main circuit breaker of generator is in “Closing Permit”, and “Remote Operation Permit”.

Check that there is no fault with generator AVR.


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Check that the excitation mode selected is “Constant Generator Terminal Voltage Operation Mode”

The magnetic blow-out switch of generator is closed.

The generator excitation launches.

The generator voltage is raised to 20kV.

“Request Synchronization” is send to DEH.

The generator parallel switch is selected.

The generator ASS is put into operation.

Check that the closing of generator circuit breaker is normal.

The generator ASS is cut off.

The generator PSS device is put into operation.

2.4 Normal Operation Mode of Generator

2.4.1 Permissible Temperature and Temperature Rise

During generator operation, it must specially pay attention to the temperature and temperature rise of each part of generator not to exceed the permissible value so as to ensure the safety operation of generator.

The temperature of generator stator winding is measured by a temperature detector (thermocouple or resistance element) embedded among wires, and the temperature of rotor iron core is measured by a sector phenolic aldehyde laminated sheet with temperature detector embedded in the iron core.

The temperature of rotor winding is normally measured in accordance with the resistance change under cold state and hot state, or is calculated in accordance with the readings of rotor voltage meter and rotor current meter.

The maximum permissible monitoring temperature for rotor, stator winding and stator iron core is the temperature generated when the generator operates continuously under the conditions of the rated cooling gas temperature and rated power.

The permissible temperature value of each part of generator depends on the class of insulation material used by winding.

The maximum permissible temperature of each part of winding is stipulated as follows when the generator operates as per the rated data on the nameplate:

Maximum permissible temperature of stator winding 120℃

Maximum permissible temperature of rotor winding 130℃

Maximum permissible temperature of stator iron core 120℃

The permissible temperature rise is difference between the maximum permissible temperature and the rated temperature of cooling medium.

The standard of current increase or decrease comparing to the rated value is subject to the temperature of winding not to exceed the original maximum permissible temperature specified when the temperature of generator cooling medium changes.

The inlet air temperature of hydrogen cooling generator should not be lower than 20℃.

2.4.2 Permissible Change Range of Voltage

The change range of generator operation voltage is ±5％ of rated voltage while the power factor is rated value, and the rated capacity of generator keeps not to change, i.e. the stator current can increase 5% when the voltage decreases 5%; the stator current can decrease 5% when the


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voltage increases 5%.

The maximum permissible voltage for generator continuous operation should comply with the stipulations of manufacturer, but the maximum voltage must not be more than 110% of the rated value; the minimum operation voltage of generator should be decided in accordance with the requirements of stable operation, and should not be lower than 90% of the rated value.

2.4.3 Permissible Change Range of Frequency

The generator can operate according to the rated capacity when the change range of frequency does not exceed 50±0.2Hz.

2.4.4 Operation Mode Decided by Change of Power Factor

The power factor of generator should be kept in 0.85 lagging phase. In order to ensure the stable operation, it is stipulated that the power factor of generator must not exceed 0.95 lagging phase.

The output of generator should be decreased when the power factor is lower than the rated value.

The output of generator will keep unchanging when the power factor changes between the rated value and 1.

2.4.5 Permissible Unbalanced Load Range

The permissible unbalanced current value of generator should comply with the stipulations of manufacturer.

When there is no stipulation from the manufacturer, as for the generator with air cooling and hydrogen surface cooling, the following stipulations should be implemented:

a）When the generator continuously operates with rated load, the difference between three phase currents of steam turbine generator must not exceed 10% of the rated current, at the same time, any phase of current must not be more than the rated value.

b）When the generator operates with a load to be lower than the rated load, the difference between three phase currents can be more than the abovementioned stipulation, but the detailed value should be decided in accordance with the test which should meet the following constraint conditions:

c）As for a steam turbine generator with wound rotor, it is prohibited to operate under the unbalanced load.

The permissible short-time unbalanced generator current value should comply with the stipulations of manufacturer.

When there is not stipulation from the manufacturer, as for the generator with air cooling and hydrogen surface cooling, it can be calculated as per I2*2t≤30.

In which, I2*—per unit value of negative sequence current; t—duration time of I2

Internal cooling generator I2*2t＝3 to 10.

When operators finds the unbalance of three phase currents exceeds the permissible value during the operation of generator, the causes should be found out and eliminated immediately, otherwise, the load should be decreased as specified.

Permissible time when unbalance of three loads exceed 10% above

Ibig＝Ie

Two phase currents are equal, and are smaller than the third phase current (Ismall/ Ie)

＜0.51 0.51 0.56 0.62 0.73 0.82 0.912

I 大＝Ie

Two phase currents are equal, and are smaller than the third phase current（Ismall/ Ie）

＜0.27 0.27 0.44 0.55 0.68 0.81 0.908


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I2 Per unit value of negative sequence current（I2/ Ie）＞0.45 0.45 0.35 0.28 0.20 0.12 0.06

Permissible time

Permissible duration time (min)

Immediately shutdown 1 2 3 5 10

Long term

operation

2.4.6 Permissible Overload

It is not permitted that the generator operates with overload in normal operation.

There is not big influence to the life time of insulation for short-time overload.

The permissible value of short-time overload should comply with the stipulation of manufacturer.

When there is no stipulation from the manufacturer, the generator with air cooling and hydrogen surface cooling can make reference to the following table to execution.

Short-time overload current of stator winding/rated current

1.10 1.12 1.15 1.25 1.50

Duration time（min） 60 30 15 5 2

When the stator current of generator exceeds the permissible value, operators should at first check the power factor (cosφ) and voltage of generator, the power factor should not be too high, and the voltage should not be too low, at the same time, the time of overload should be paid attention, the stator current should be reduced to the maximum permissible value by means of the method of reducing the excitation current within the permissible time in accordance with the stipulations on site, but the power factor must not be too high and the voltage must not be too low. In case the stator current can not be decreased to the permissible value by reducing the excitation current, the active power of generator must be reduced or a part of load must be cut off.

The permissible value of short-time overload for an internal cooling generator should be implemented in accordance with the stipulations of manufacturer. If there is no stipulation from the manufacturer, it should be decided by calculating.

2.4.7 Reinforced excitation capability of generator

The generator can endure a reinforced excitation voltage of 2 times of rated exciting voltage and the duration time is 10s. The rise speed of reinforced excitation voltage is not less than 2/sec.

2.4.8 General Manual of Generator Operation

The mode that generator operates in accordance with the nameplate parameters of manufacturer is the rated operation mode; the generator can continuously operate over a long period of time under the rated operation mode or in the range of the capacity limit curve.

It is not permitted the generator operates with load without internal cooling water of stator.

It is not permitted the generator operates without excitation in the normal condition.

The operation time of steam turbine unit with reverse power must not more than 1 minute.

Leading phase operation of generator must be otherwise stipulated after it is tested up to standard.

2.5 Monitoring in Operation

2.5.1 General

The operation conditions of generator should be monitored in operation, and each part of generator should be systematically checked so as to find any abnormal phenomena and eliminate the abnormity as soon as possible.

2.5.2 Recording of Operation Parameters

a)All operation parameters of generator should be recorded once every hour, and the power and current values should be recorded once a half hour at the maximum load.

b)The temperatures of stator winding, stator iron core and inlet and outlet air must be checked


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once every hour, and recorded once every two hours. If an automatic recording meter is installed, the recording interval can be properly extended.

c)The insulation resistances of stator and excitation circuit should be measured once each shift.

d)All recordings of meter readings for all automation units should be carried out at the periodical patrol inspection.

2.5.3 Patrol Inspection Items of Generator

2.5.3.1 Check in Operation of Generator

1) The indication of each meter should not exceed the permissible and the relationship should be correct.

2) Each light signal and switch position feedback should conform to the actual indication position and be correct.

3) The voltage and current meters of three phases of generator should balance.

4) There is no abnormity with the acoustic-optic alarm.

5) The relay room and automation device should be normal without overheating and fuming phenomena.

6) Each switch position conforms to the actual operation mode.

7) The operation of DC system is normal.

8) The operation of regulator is normal, and each indication instrument conforms to the actual condition.

9) The sound of generator is normal, and the vibration of unit does not exceed the permissible value.

10) There is no overheating, discharge and spark phenomenon with switches, busbars, instrument transformer and cables in the excitation system.

11) Equalizing springs of generator carbon brushes are firmly installed and the pressure is appropriate, there is no overheating with carbon brushes and slip rings, and there is no spark between the slip ring and the carbon brushes.

12) It is to be checked from the sight holes on the ends whether or not there is any dew and water leakage phenomenon on the two sides of generator body, there is any vibration and abrasion phenomenon with the insulated diversion pipes, and there is any local overheating point on the clamping ring.

13) The cold and hot hydrogen temperatures are normal.

14) The stator winding temperature and the hydrogen outlet temperatures of stator winding are normal.

15) The cooling water pressure, temperature difference and terminal difference of cooler should be normal.

2.5.3.2 Check of Excitation System

1) Check items of exciting regulator

①All indication meters in the panel are normal.

②There is no overheating of all elements and unexpected noise and peculiar smell in the panel.

③All indications in the panel conform to the operation mode.

④There is no abnormal signal lamp to light in the panel.

⑤Positions of all miniature switches in the panel conform to the operation mode.


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⑥The ambient temperature, humidity and vibration do not deteriorate.

2) Check items of rectifying cabinet

① Indications of all meters in the rectifying cabinet are normal.

② All indicator lights for operation should be light; the reactive power cabinet is out of service, and there is an indication that quick-acting fuse is blown.

③ The signals of rotor overvoltage protection cabinet are normal without abnormity phenomenon.

④ Operation of each fan of rectifying cabinet is normal.

⑤ There is no heating phenomenon with each connection.

3) Check items of magnetic blow-out switch

① There is no heating and discoloration with connections.

② There is no burnt odor and abnormity of mechanism.

③ There is no abnormal rise of ambient temperature, in general, it does not exceed 40℃.

④ The excitation initiating device is in good condition.

4) Check items of carbon brushes and slip rings in excitation circuit

① There is no crack and rupture with equalizing springs of carbon brushes; there is no spark on the contact surfaces of carbon brushes; there is no bounce and fragmentation of carbon brushes, and they can freely carry out up and down move. The carbon brushes are not shorter than the limitation line; carbon brushes and brush flexible do not heat and discolor; there is no broken strand with brush flexible; there is no looseness on the roots of brush flexible; the types of carbon brushes are same.

② There is no crack on the brush holder, and it is clean.

③ The brush rings are clean and round without scuffing and heating phenomenon.

2.6 Parallel Off and Shutdown of Generator

2.6.1 Parallel Off and Shutdown of generator (reverse power protection acting)

(1). Check that the power supply of 6kV working busbar section is switched from the working power supply to the standby power supply.

(2). The active load of generator is decreased to zero.

(3). The reactive load of generator is decreased to ＜5Mvar.

(4). The protection of generator “inadvertent energization and startup/shutdown” is put into operation.

(5). It is informed to the steam turbine chief operator of this unit that the trip of steam turbine can be carried out.

(6). Check that the reverse power protection has acted after the main stop valve of steam turbine is closed.

(7). Check that the main circuit breaker of generator-transformer unit has opened, and currents of three phases are 0.

(8). Check that the generator terminal voltage has decreased to approach 0.

(9). Check that the magnetic blow-out switch has reliably opened.

(10). The PSS device is out of service.


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(11). It is to be checked at local that the main circuit breaker of generator-transformer unit has reliably opened.

(12). The isolating knife switch at the HV side outlet of the main transformer is opened.

(13). It is to be checked at local that three phases of isolating knife switch at the HV side outlet of the main transformer have reliably opened.

(14). The power cut operation for the circuit breaker of working power supply of 6kV working busbar section A is carried out.

(15). The power cut operation for the circuit breaker of working power supply of 6kV working busbar section B is carried out.

(16). The operation of HV auxiliary power transformer cooler is stopped.

Note: the stop time of main transformer cooler is executed in accordance with the operation Manual of transformer.

2.6.2 Parallel Off and Shutdown of Generator (Reverse Power Protection Refusing Action)

(1). Check that the power supply of 6kV working busbar section is switched from the working power supply to the standby power supply.

(2). The active load of generator is decreased to zero.

(3). The reactive load of generator is decreased to ＜5Mvar.

(4). The protection of generator “inadvertent energization and startup/shutdown” is put into operation.

(5). It is informed to the steam turbine chief operator of this unit that the trip of steam turbine can be carried out.

(6). It is confirmed that the main stop valve has closed, and the reverse power of generator has occurred (non positive value)

(7). The main circuit breaker of generator-transformer unit is switched off, Check that the currents of three phases of main circuit breaker are 0.

(The judgment of step 6 and the operation of step 7 should be completed in one minute.)

(8). Check that the generator terminal voltage has decreased to approach 0.

(9). Check that the magnetic blow-out switch has reliably opened.

(10). The PSS device is out of service.

(11). It is to be checked at local that the main circuit breaker of generator-transformer unit has reliably opened.

(12). The isolating knife switch at the HV side outlet of the main transformer is opened.

(13). It is to be checked at local that three phases of isolating knife switch at the HV side outlet of the main transformer have reliably opened.

(14). The power cut operation for the circuit breaker of working power supply of 6kV working busbar section A is carried out.

(15). The power cut operation for the circuit breaker of working power supply of 6kV working busbar section B is carried out.

(16). The operation of HV auxiliary power transformer cooler is stopped.

(17). The electrical maintenance persons are informed to search for the causes of refusing action for reverse power protection.

2.6.3 Power Cut of Generator-Transformer Unit

(1). Check that the isolating knife switch in the main transformer HV side is in open position;


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(2). The power cut operation of PT in the main transformer HV side is carried out;

(3). The power cut operations for cooling devices of main transformer and HV transformer are carried out;

(4). The power cut operation for the excitation regulating system is carried out; (Note: The industrial computer of the excitation regulating system will be shut down before power cut to avoid the data losing of the industrial computer at power turnoff);

(5). The secondary miniature switch of generator outlet PT is switched off, and the PT trolley is drawn to the isolation position and locked, the PT HV side fuses are taken off;

(6). It is to be checked the working branch circuit breaker of 6KV busbar section A and B has cut power, and the power cut operation of the working branch incoming line PT is carried out;

(7). The relevant protections are stopped;

(8). Safety measures are taken in accordance with the requirements of maintenance.

2.6.4 Shutdown in Normal Condition

Before the generator parallels off, the auxiliary power should be at first switched over to the standby power supply, and then the active load should be reduced to zero, the reactive load should be reduced to approach zero, the trip of steam turbine is informed, the generator shall parallel off by action of the reverse power protection. Check that the generator voltage is reduced to zero, the magnetic blow-out switch shall be switched off, and the cooling device of main transformer and HV transformer shall be stopped.

After the generator is completely shut down, the insulation resistances of stator winding, rotor winding and other parts should be immediately measured in the hot state. Meanwhile, Check whether the water in gas cooler has stopped circulating, and it should be recorded in a specified record book.

2.6.5 Shutdown in Emergency Condition

Check whether all three phases of main circuit breaker are opened; whether or not the magnetic blow-out switch is opened; whether or not the generator voltage is zero. The generator and the primary system should be immediately checked to find whether or not they are damaged.

2.7 Maintenance after Shutdown

2.7.1 Long Term Shutdown

During long term shutdown, hydrogen has been discharged outside the generator, the sealing oil system and other accessory systems have stopped working, therefore, the relevant maintenance items are list as follows:

1) Exhausting Hydrogen in the generator

The upper and lower screw plugs of hydrogen sealing cover located between generator stand and end cap are unscrewed, and the hydrogen to be likely to collect in the sealing cover is discharged. All dead zones on the top of the base are purged by compressed air to exhaust the hydrogen in the generator.

2) Emptying the residual water in the water circuits of stator winding

a） The drain outlet in the lower part of collecting pipes on steam end and excitation end are opened to discharge the residual water in the collecting pipes.

b） The inlet and outlet water pipes are removed, the steam end outlet water flange is covered with cover board, an air flexible pipe is connected to the excitation inlet water flange to carry out purging, and the compressed air should be clean without oil and dust.

c） The water in the water circuits of stator winding are purged by compressed air in several


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times, till there is no water smoke in the air purged.

d） And then the residual water to be difficult to purge by compressed air are drawn out by means of a vacuumizing method.

3) Water circuit maintenance of stator winding

In order to avoid the oxidation of inner wall of hollow copper wires, the water circuits of stator winding should be periodically washed out via water inlet and outlet by nitrogen. Afterwards, the inlet and outlet water flanges are closed down.

4) Maintenance of hydrogen cooler

The hydrogen cooler is cleaned; after cleaning, the residual water is emptied and the pipes is dried by compressed air and treated by corrosion protection.

5) Anti-dew in the generator

Two manhole covers can be removed and an air heater or an air dryer is installed in the positions of two manholes to continuously dry the air in the generator. It should be considered that air can circulate through all spaces in the generator when the installation positions of air heater or the air dryer are decided.

6) Maintenance of rotor

During long term shutdown, if the rotor is placed in the generator for long period of time, it should be turned 90 degree once every three day to avoid the rotor taking place bend and permanent deform.

7) Safety measures

eh

2.7.2 Short Term Shutdown

1) General

2) The following parameters is to be periodically monitored and recorded

a） Hydrogen purity, humidity and pressure.

b） Temperature and pressure of sealing oil.

c） Temperature and conductivity of stator cooling water.

d） Hydrogen leakage measured.

3) Hydrogen sealing

The normal operation of sealing oil system is maintained, the sealing oil pressure is kept to be higher than the hydrogen by 0.056MPa, and the sealing oil temperature is higher than 30℃ to ensure sealing up hydrogen.

4) Hydrogen purity

The hydrogen purity is to be measured periodically, and the hydrogen purity in the generator should be kept in 96% above by means of supplementing fresh hydrogen.

5) Anti-dew

The relative humidity in the generator is controlled ＜50％ to prevent the inside of generator from dew. During shutdown, the relative humidity in the generator is relative to the temperature around the generator. The relative humidity in the generator is measured periodically and at the time of the ambient temperature decreased by 8℃ above. If the relative humidity in the generator is too high, some hydrogen should be discharged from it and some dry hydrogen is implemented to reduce the relative humidity.

6) Cooling water of stator winding


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Water is used for circulation cooling the stator winding and the cooling water temperature is at least maintained to be higher than the hydrogen temperature in the generator by 5℃ above to prevent the water content in the hydrogen to dew on the stator winding, meanwhile, achieve a purpose preventing the hollow copper wires of stator winding from oxidation and corrosion. If necessary, the stator cooling water can reverse to run.

The conductivity of stator winding is to be checked periodically, the conductivity of water in the water tank should be kept in the specified range.

7) Maintenance of cooler

In order to avoid the corrosion and scaling of cooling water pipe, a small flow of water should always flow through the cooler. In addition, the cooler should be washed out twice every week by water with a large flow rate.

8) Safety Measures

xi

2.8 Accident Handling

2.8.1 Adjustment under the Condition of Abnormal Operation

The abnormal operation of generator refers to an operation condition, in which the temperature, voltage, current, frequency, load nature, excitation conditions and cooling conditions of generator obviously deviate from the rated value.

2.8.1.1 Generator Temperature Abnormity

When the generator operates under the condition of rated load or approaching rated load, if the stator winding temperature or iron core temperature of generator exceeds the limit value, or the rotor temperature exceeds the limit value, the cause must be immediately found out.

If the temperature rise of generator results from the interruption of cooling water or the decrease of cooling water flow rate entering into the hydrogen cooler, then the water supply should be immediately resumed. If the water supply can not be consumed immediately or the cooling system is normal, then the generator load must be immediately decreased till the temperature is reduced to the permissible value. If the generator temperature can not be controlled in the range of permissible value after reducing load, the unit should be shut down to inspect.

2.8.1.2 Overcurrent of Stator Winding and Rotor Winding of Generator

Overload or overcurrent is not permitted in normal operation of generator; a permissible operation range is clearly marked on the power diagram. When a power grid accident occurs, some units will trip; the reinforced excitation of the generator will act in order to sustain the stable operation of the power grid and the generator and resume the voltage of power grid when the voltage of power grid is decreasing, at this moment, the overcurrent of stator and the rotor overvoltage of generator are permitted in a short time.

The multiple and the duration time for the short time operation with permissible overcurrent and overvoltage are relative to the heating of stator and rotor windings as well as the heat resistances of insulation materials.

The multiple and the duration time of permissible overcurrent of stator are calculated as per （I2-1）t＝37.5s.

In which I2—per-unit value of stator overcurrent; t—duration time, it is applicable to the range of 10 to 60s

Multiple of overcurrent 2.00 1.50 1.40 1.32 1.27 Duration time（s） 12.5 30 39 50 60

Note: The stator temperature will exceed the value at the rated load under the abovementioned overcurrent condition; therefore, a limitation of twice overcurrents per year should not be


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exceeded.

When the generator operates with stator overcurrent, operators should at first inspect the power factor and the voltage of generator, and record the time and the magnitude of overcurrent. The excitation current should be reduced and the stator current will be reduced to the normal value within a permissible duration time in accordance with the stipulations in site Manual, but the stator voltage must not exceed the minimum permissible value.

If the stator current can not be reduced to the normal value by decreasing excitation current, the active load of generator must be reduced.

Multiple and permissible time of rotor overvoltage

The reinforced excitation time of generator is not less than 10s when an accident occurs, in general, the reinforced excitation multiple (the ratio of maximum of reinforced excitation voltage to the excitation voltage) does not exceed 2.

Multiple and permissible time of short-time overvoltage for internal cooling type rotor winding

Multiple of overvoltage 1.12 1.25 1.46 2.08 Permissible time（s） 120 60 30 10

2.8.1.3 Asymmetry Operation of Generator

When the generator carries out asymmetry operation, the maximum phase current in stator current is likely to exceed the rated value, which should be limited according to the relevant stipulations in short-time or continuous overcurrent.

The capability that a generator bears negative sequence current is decided by the maximum permissible temperature of rotor surface structural member.

When the generator outlet circuit breaker can not be fully opened or closed at the same time and results in the non-all-phase operation fault of generator, operators should immediately decrease the output power of steam turbine and the excitation current of generator to make the active power and the reactive power of the unit approaching zero so as to minimize the negative sequence current. For this reason, the main stop valve of steam turbine should not be closed and the excitation current of generator should not be switched out in order to avoid the negative sequence current not to be able to decrease effectively.

2.8.2 Handling under Accident Condition

2.8.2.1 Emergency Shutdown

Smoke emission and catch fire or hydrogen explosion in the generator occur.

Generator sealing oil is interrupted and can not be rapidly consumed.

Generator slip ring generates intense circle sparks and can not be eliminated.

Generator unit generates severe vibration (exceed permissible value).

Steam turbine or boiler trips, but the main circuit breaker of generator does not trip.

There are serious water leakage from the stator bar and lead wire.

The electrical connecting equipments related to generator such as main transformer, HV auxiliary power transformer etc. take place serious fault.

Other accidents to endanger personal and equipment safety occur.

2.8.2.2 Applying for Shutdown

Generator is operating without protection.

The temperature and the temperature rise of the unit exceed the permissible value, and there is no effect after taking measures.

Rotor interturn short circuit is serious and the rotor current has reached the rated value, and the


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reactive power is still very small.

The hydrogen pressure in the generator is too low to keep the normal operation of generator, or the hydrogen quality in the generator has deteriorated and can not resume the normal value after taking measures.

2.8.2.3 Generator Outlet Circuit Breaker Trip

a) Phenomena

The circuit breaker of auxiliary standby power supply is closed by interlock.

The indications of all meters of generator are zero.

The action indicator lamps of relevant protections illumine (or signals send out).

b) Solution

Sound signals are released.

Check that the auxiliary standby power supply is put into operation by interlock, if no action, if the quick-trip protection and overcurrent protection do not act, and there is no lock signal from quick switchover device, and there is no obvious short circuit symptom, then the circuit breaker of standby power supply can be manually closed to resume the auxiliary power. If the working branch circuit breaker does not open, the working branch circuit breaker should be at first opened, and the standby branch circuit breaker is closed quickly.

It is to be judged in accordance with the relevant meters and protection actions whether or not the protection action is correct, whether or not the action of each circuit breaker is normal, and all these should be reported to the shift supervisor.

The fault nature and range is analyzed and judged in accordance with protection action, a detailed check will be carried out; the maintenance personnel and test personnel should get together to eliminate fault as soon as possible.

If the generator trips by protection action due to the system fault, the dispatcher should be contacted in time, the synchronization will be carried out over again after the fault is eliminated.

If the generator trips due to the protection false action, the synchronization will be carried out over again after the chief engineer agrees.

If it is confirmed the generator trips due to factitious false action, the synchronization can be carried out at once after the dispatcher agrees without checking.

2.8.2.4 Generator Excitation Loss

a) Phenomena

1﹚DCS accident alarm sounds and alarm signal sends out.

2﹚The indication value of generator rotor current equals to zero or approaches zero.

If the excitation circuit of exciter breaks, the voltage indication and the current indication of rotor are zero;

If the rotor circuit breaks, the rotor voltage will rise, and the current is zero;

If a short circuit of rotor circuit occurs, the rotor voltage will drop, and the current will rise;

When the excitation loss results from the interturn short circuit of rotor winding, the rotor current is not zero.

3﹚The stator current indication rises and is likely to exceed the rated value and periodic swings occur.

4﹚The active power indication reduces and swings.

5﹚The generator terminal pressure indication slightly reduces and swings.


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6﹚The reactive power indication is negative value.

7﹚The parameters of excitation circuit show abnormity.

8﹚When the trip is caused by the excitation loss protection, in addition to the abovementioned instantaneous phenomena, the main circuit breaker and the magnetic blow-out switch will state up the quick switching device to switch off the auxiliary working branch circuit breaker and switch on the circuit breaker of standby power supply.

b) Solution:

1﹚The generator excitation loss protection acts, the unit disconnects with the system, it is to be handled as per generator accident trip.

2﹚If the generator excitation loss protection does not act, the excitation should be immediately manually increased, if without effect, the generator immediately parallel off.

3﹚When the excitation loss protection acts to send signals or is not put into operation, manual parallel off, demagnetization and shutdown should be carried out.

4﹚The generator should immediately disconnect with the power grid system when the generator excitation loss gives rise to oscillation.

5﹚The generator excitation system is to be checked after parallel off, and the generator will be restarted to synchronize after the fault is eliminated.

2.8.2.5 Generator Oscillation

a) Phenomena

The indications of stator voltage meter, current meter, active power meter, reactive power meter, busbar voltage meter rhythmically swing, and judder under the serious condition.

The voltage usually drops and the current rises.

The frequency meter indication rises or drops, and slightly swings.

The generator sends out rhythmical purr which is in step with the meters.

If the oscillation results from the out-of-step of this generator, the swing amplitude of this generator is more severe than the neighbor generator, and the swing direction of active load of this generator displayed is reverse to the neighbor generator; if it is system oscillation, the swings of two generators is synchronous.

b) Solution

The generator excitation circuit instruments are checked, if the oscillation results from the false parallel on or excitation loss of generator, the generator should immediately disconnect with the power grid system.

In the case of the generator oscillation results from an accident of the power grid system, if the excitation regulation is in automatic mode, it is strictly prohibited to switch to the manual mode, the excitation current should be increased as possible; if the automatic excitation is put into operation, the reinforced excitation will act, it is strictly prohibited to intervene the action of excitation circuit regulator in 20 seconds.

The active load is to be decreased to eliminate the oscillation, but the frequency can not be lower than the responding value of frequency protection.

If the oscillation of the generator and the power grid system occur, the generator can not be pulled in step in a specified time after operators takes abovementioned measures, the generator should parallel off immediately. The steam turbine and the boiler will be handled as per shutdown (the vacuum is not damaged).

If the oscillation results from the power grid system, the generator excitation current should be


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increased to keep the system voltage, and the handling will depend on the command of dispatcher.

2.8.2.6 Generator Non-synchronous Parallel

a) Phenomena

The parameters of generator takes place a great number of change and oscillation, the reinforced excitation of automatic excitation regulator is likely to act.

The unit generates vibration and accompanies with roar.

The generator out-of-step protection is likely to act.

b) Solution

When the generator out-of-step protection acts to trip, the handling will be carried out as consistent with a trip of the main circuit breaker.

If the generator has not obvious sound and vibration, and the oscillation amplitudes of all parameters indicated gradually attenuates, the generator can not shut down.

If the generator gives birth to very strong impact and severe vibration, and it is shown that the swings are terrible without attenuation, the generator should immediately parallel off and shut down.

When a generator without excitation takes place false parallel on, it should immediately parallel off.

If a non- synchronous parallel gives rise to a trip of the generator-transformer unit, the protection actions should be immediately checked, and the conditions should be reported to the shift supervisor, the generator-transformer unit will be roundly checked and tested so as to decide whether or not synchronization will be carried out again. The AC impedance of generator rotor is to be measured. The deputy general manager in charge of production should be asked for instructions concerning whether or not the generator can restart and parallel on.

2.8.2.7 Generator Reverse Power Operation

a) Phenomena

The active power indication is negative value or zero, the active energy meter reverses.

Reactive power indication rises.

Stator current decreases.

Indications of stator voltage and excitation meters are normal.

The main stop valve of steam turbine is closed.

The frequencies of the power grid system and the generator decreases slightly.

b) Solution

When the reverse power operation of generator occurs, if the reverse power protection does not act, the handling should be carried out as per the following procedures.

The auxiliary power is to be switched over to the standby power supply.

The generator is to be disconnected with the power grid system.

The magnetic blow-out switch is switched off.

The operation time of reverse power must not exceed 1 minute.

The causes should be found out after the generator parallel off, and the generator can be restarted to parallel on after the fault is eliminated.

2.8.2.8 Motor Rotor One-Point Earthing

a) Phenomena


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DCS sends out a signal of “Rotor One-Point Earthing”.

The rotor earthing signal lamp is light on the protection panel.

b) Solution

The rotor two-point earthing protection is put into operation (automatically put into operation).

The excitation system is to be roundly checked whether or not there is any obvious earthing point.

The monitoring of excitation system is strengthen, if the rotor current is found to increase, and the reactive power obviously decrease, the generator immediately parallels off and shuts down.

When an external earthing of rotor winding occurs, the maintenance personnel should be contacted to eliminate or isolate the earthing point so as to ensure the normal operation of this unit.

The rotor excitation circuit will be checked in detail, if the earthing results from the dirt retention on the slip ring or excitation circuit, the dry air which is lower than 0.294MPa can be used for purging to resume insulation. If necessary, the rectifying cabinet can be disabled in check so as to judge whether or not the earthing is located in the DC circuit of rectifying cabinet. In case field loss or out-of-step occurs during the handling process, the generator should be shut down.

If it is confirmed the generator rotor winding exists earthing fault, the generator should try for shutdown as soon as possible.

2.8.2.9 Two-Point Earthing in Excitation Circuit

a) Phenomena

The rotor current indication sharply increases, the excitation voltage indication decreases, and fluctuation is likely to appear; the reactive load indication decreases or reverses, and the generator voltage decreases; the unit acutely vibrates.

b) Solution:

If the protection acts to trip, the handling will be carried out as per the fault shutdown, and safety measures of maintenance should be taken.

When the rotor two-point earthing protection refuses action, the abovementioned phenomena occur, the generator should immediately parallel off to shut down.

2.8.2.10 Generator Stator Earthing

a) Phenomena

1)A protection alarm “Generator Stator Earthing” sends out.

2)The generator protection acts to trip.

b) Solution

When the stator earthing protection acts to trip, the handling will be carried out as per generator trip.

If an alarm “Generator Stator Earthing” accompany with another alarm “There Is Oily Water in Generator” successively occur, the generator should carry out an emergency shutdown.

When the stator earthing protection has send out signals without trip, an appearance inspection to the generator outlet PT and the excitation transformer should be immediately carried out, the relay protection personnel should be informed to measure the secondary voltage of generator neutral point distribution transformer and the secondary voltage of generator outlet PT. The generator should immediately parallel off and demagnetize when it is confirmed there is an internal earthing in the generator after comprehensive analysis and judgment.

If only alarms send out, the action condition of triple harmonic stator earthing should be checked immediately, a detailed inspection should be carried out nearby the neutral point, and electrical


- 41 -

maintenance personnel should be informed to carry out inspection.

After shutdown, the maintenance personnel should be contacted to separately measure the generator outlet PT, the excitation transformer insulation and the generator stator insulation to judge the fault taking place the outside or the inside of generator.

2.8.2.11 Generator Water Shut Off

a) Phenomena

An alarm “Stator Winding Water Circuit Water Shut Off” on DCS and sound alarm send out.

The cooling water flow rate in the stator winding is lower than 35t/h.

The working stator cooling water pump is likely to trip.

If it does not resume in 30 seconds, the water shut off protection acts to trip, and there is “Water Shut off Protection Action” drop.

b) Solution

The standby stator cooling water pump is immediately started up.

The internal cooling water is tried to resume to the normal value as soon as possible in a possible short time.

It is to be found out whether or not the protection device or check and measurement part takes place false action. If false action is confirmed, then the water shut off protection will be out of service and the relevant personnel will be informed to carry out treatment at once. The water shut off protection should be put into operation immediately after the treatment is completed.

If the water shut off is true, when the protection fails to act, the generator will be immediately shut down.

2.8.2.12 Generator Inner Explosion and Catching Fire

a) Phenomena

There is violent abnormal explosion sound in the inside of generator, and there are smoke emission and burnt odor on the two sides.

The cooling gas pressure in the generator rises or greatly decreases, and the outlet temperature rises.

The hydrogen purity decreases, and the voltage fluctuation is terrible along with explosion.

b) Solution

If the protection does not act, the trip of steam turbine should be immediately carried out, the excitation is cut off, and the generator keeps a specified rotary speed (200r/min).

The hydrogen is rapidly discharged, the hydrogen filling valve will be tightly closed, and CO2 will be filled into the generator.

Fire fighting will be carried out in accordance with the stipulations in fire fighting Manual.


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Chapter III Transformer 1 Equipment Specifications 1.1 Equipment Technical Parameters of Main Transformer

Model SFPZ10-370000/150 TH

Type Outdoor three-phase double-coil copper winding on-load voltage regulating oil-immersed low loss transformer

Cooling mode Forced directed oil circulation air cooling (OFAF) Rated frequency 50Hz Rated capacity 370MVA Rated voltage ratio （1508×1.25%）/20 kV

Insulation level

HV line terminal LI/AC 950/395KV Numbers of Phases

3

HV neutral point terminal

LI/AC 400/200KV No-load loss

160.95kw

I.v.line terminal LI/AC 200/85KV No-load current

0.14％

Connection symbol Ynd1

Short circuit impedance 14.19％

No-load current 20.76A Manufacturer Shandong Power Equipment Company

Voltage Taps of Transformer

High voltage Low voltage Position of

switch Connection Voltage（V） Current （A） Voltage（V） Current （A）

1

X1-Y1-Z1 165000 1294.7

200000 10681

2 X2-Y2-Z2 163125 1309.5 3 X3-Y3-Z3 161250 1324.8 4 X4-Y4-Z4 159375 1340.4 5 X5-Y5-Z5 157500 1356.3 6 X6-Y6-Z6 155625 1372.7 7 X7-Y7-Z7 153750 1389.4 8 X8-Y8-Z8 151875 1406.5

9A X9-Y9-Z9 150000

1424.1 9 XK-YK-ZK

9B X1-Y1-Z1 10 X2-Y2-Z2 148125 1442.2 11 X3-Y3-Z3 146250 1460.6 12 X4-Y4-Z4 144375 1479.6 13 X5-Y5-Z5 142500 1499.1 14 X6-Y6-Z6 140625 1519.1 15 X7-Y7-Z7 138750 1539.6 16 X8-Y8-Z8 136875 1560.7 17 X9-Y9-Z9 135000 1582.4

1.2 Equipment Technical Parameters of HV Auxiliary Power Transformer

Model SFFT10-50000/20 TH Type Three-phase oil immersed air cooling copper core low loss LV side split

K+

K-


- 43 -

Model SFFT10-50000/20 TH winding no-load voltage regulating transformer

Cooling mode Oil immersed air cooling (OGAF) Rated frequency 50Hz Rated capacity 50000/27000-27000kVA Rated voltage （20±2×2.5%）/6.3-6.3kV

Insulation level HV line terminal L1/AC 200/85KV I,v line terminal L1/AC 75/35KV I,v neutral point terminal L1/AC 75/35KV

Use condition outdoor Altitude ﹤1000m Connection symbol Dyn1－yn11 manufacturer Shandong Power Equipment Company

Voltage Taps of HV Auxiliary power transformer

High Voltage Position of switch Connection Voltage

(V) Current (A)

Ⅰ A2-A3 B2-B3 C2-C3 21000 1100.00 Ⅱ A3-A4 B3-B4 C3-C4 20500 1126.50 Ⅲ A4-A5 B4-B5 C4-C5 20000 1154.7 Ⅳ A5-A6 B5-B6 C5-C6 19500 1184.3 Ⅴ A6-A7 B6-B7 C6-C7 19000 1215.5

Low voltage 1 Low voltage 2 Voltage (V) Current (A) Voltage (V) Current (A)

6300 2291.1 6300 2291.1

1.3 Equipment Technical Parameters of Startup Standby Transformer

Model SFFZ10－40000/154 TH Use condition Outdoor Rated

capacity 40000/25000－25000/15000KVA Cooling mode ONAF (oil

immersed natural

cooling) Rated voltage 154×（1±8×1.25％）/6.3-6.3 Frequency 50HZ Rated current 2291.1A (LV side) Connection

symbol YNyn0-yn0+d

Insulation level

HV line terminal LI/AC 950/395KV Numbers of Phases

3

HV neutral point terminal

LI/AC 185/85KV

I.v. line terminal LI/AC 75/35KV I.v. neutral point terminal

LI/AC 75/35KV

Balance coil line terminal

LI/AC ?KV

Load loss

High - (low 1+low 2) at 50000KVA

220.93KW

High – low 1 at 27000KVA 105.21KW Body Hoisting weight

41450kg

High – low 2 at 27000KVA 111.70KW Total oil weight 22410kg Cross

impedance High voltage－(low voltage 1＋LV2)

9.26％ Total weight 85930kg

Semi-cross impedance

High voltage－low voltage1 20.50％ Upper oil tank weight

6120kg High voltage －low 1 20.44％


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Split impedance

Low voltage 1－low voltage 2 45.09％ Anti seismic

capability

Level 10

Noise ≤75Db(100％ cooling mode, 2m distance from transformer body)

Manufacturer’s Serial number of

24A234

Altitude (254.85－297.76)m Year and month of Manufacture

2004.12

Product code 1XTB.710.3143

Voltage Taps of Startup Standby Transformer

High voltage Low voltage Position of

switch Connection Voltage (V) Current (A) Voltage (V) Current (A)

1

X1-Y1-Z1 169400 136.3

200000 10681

2 X2-Y2-Z2 167475 137.9 3 X3-Y3-Z3 165550 139.5 4 X4-Y4-Z4 163625 141.1 5 X5-Y5-Z5 161700 142.8 6 X6-Y6-Z6 159775 144.5 7 X7-Y7-Z7 157850 146.3 8 X8-Y8-Z8 155925 148.1

9A X9-Y9-Z9 154000

150

9 XK-YK-ZK

9B X1-Y1-Z1 10 X2-Y2-Z2 152075 151.9 11 X3-Y3-Z3 150125 153.8 12 X4-Y4-Z4 148225 155.8 13 X5-Y5-Z5 146300 157.9 14 X6-Y6-Z6 144375 160.0 15 X7-Y7-Z7 142450 162.1 16 X8-Y8-Z8 140525 164.3 17 X9-Y9-Z9 138600 166.6

1.4 Technical Parameters of LV Auxiliary Power Transformer

Designation Specification and Technical Requirements Quantity (set) Unit transformer 2000kVA, 6.322.5%/0.4KV Ud=8%，Dyn11 6

Electrostatic precipitation transformer

2000kVA, 6.322.5%/0.4KV Ud=8%，Dyn11 6

Common transformer

2500kVA, 6.322.5%/0.4KV Ud=10%，Dyn11 2

Coal conveying transformer

800kVA, 6.322.5%/0.4KV Ud=6%，Dyn11 2

Water treatment and service water transformer

1600kVA, 6.322.5%/0.4KV Ud=8%，Dyn11 2

Lighting transformer 400kVA, 6.322.5%/0.4KV Ud=4%，Dyn11 3 Circulation water

transformer 630kVA, 6.322.5%/0.4KV Ud=4.5%，Dyn11 2

Lighting standby transformer

400kVA, 6.322.5%/0.4KV Ud=6%，Dyn11 1

2 Manual for Transformer Operation The transformers should comply with the technical parameters specified by the manufacturer in normal operation, and transformers can operate over a long period of time under the technical

K-

K+


- 45 -

parameters specified on the nameplate.

2.1 Manual for Normal Operation Temperatures of Transformers

2.1.1 The maximum permissible value of upper layer oil temperature for oil immersed natural cooling transformer must not exceed 95℃, normally not exceed 85℃. The temperature rise must not exceed 55℃.

2.1.2 The upper layer oil temperature of forced oil circulation air cooling transformer must not exceed 75℃ normally, and the maximum must not exceed 85℃. The temperature rise must not exceed 55℃.

2.1.3 The insulation class of insulation system for dry transformer is class F, the temperature rise of all parts must not exceed 100℃. The temperature in operation must not exceed 110℃ normally, and the maximum must not exceed 130℃. The average temperature rise of coiling, iron core surface and structural member surface must not exceed 80K. The ambient temperature is a factor influencing transformer operation, the load capacity of transformer can be smaller or bigger than the rated capacity when the yearly average temperature is higher or lower than 20℃; the transformer capacity decreased or increased is 0.6% for rising or dropping 1℃.

2.2 Manual for Transformer Insulations

2.2.1 A transformer, which is installed newly or experienced a overhaul as well as has stopped for a long period of time (two weeks above), can be put into operation after the winding insulation resistance and absorption ratio are measured up to standard before it is put into operation.

2.2.2 The insulations of high voltage against ground, low voltage against ground and between high voltage and low voltage windings should be separately measured when the insulation resistances are measured; it must be paid attention to that the voltage transformer to be related to the measurements should be in open position. When one side of winding insulation is measured, another side of winding should be short circuit and earthed, a discharge against ground should be adequately carried out after the measurements are completed.

2.2.3 Converting to same temperature and comparing with the last measured results, the insulation resistance value of oil immersed transformer should not be lower than 40%. Otherwise, the maintenance personnel should be informed to carry out check and treatment, if necessary, the medium loss and insulation resistance absorption ratio of transformer should be measured, and the oil is drawn out for chemical examination to judge whether or not the insulation is satisfactory. The absorption ratio (R60″/R15″) should not be less than 1.3 under the condition of 10℃ to 30℃, and the results, the upper layer oil temperature and ambient temperature at measurement will be recorded in a special record book to be convenient for analysis and comparison.

2.2.4 The transformer windings for the rated voltage class 1000V and above will be measured by 2500V megger, the windings for 1kV and below will be measured by 1000V megger. The winding insulation resistance values of oil immersed transformer should not be less than specified values in the following table:

Winding voltage

class

Insulation resistance values under different temperatures (MΩ)

10℃ 20℃ 30℃ 40℃ 50℃ 60℃ 70℃ 80℃

20~35KV 600 400 270 180 120 80 50 35 60~220KV 1200 800 540 360 240 160 100 70

2.2.5 The insulation of dry transformer will be judged whether or not its insulation is satisfactory in accordance with a standard not to be less than 1MΩ/KV (operation voltage). A try transformer can be put into operation after conforming there is no aging with its insulation. The manufacturer must be contacted when dry transformer windings are affected with damp and needs to treat.

2.2.6 The temperature conversion of insulation resistance can be carried out as per the following


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formulae:

Rt1=Rt2k (The temperature is higher than last time at the time of measurement)

Rt1=Rt2/k (The temperature is higher than last time at the time of measurement)

Rt1：It is to be converted to the corresponding insulation resistance under the last time of temperature

Rt2: Insulation resistance value measured in this time

t2: Temperature measured in this time（℃）

t1: Temperature at the last time of measurement（℃）

k: Temperature conversion factors for insulation resistance of oil immersed power transformer are shown as the table below:

Temperature difference

5 10 15 20 25 30 35 40 45 50 55 60

Conversion factor

1.2 1.5 1.8 2.3 2.8 3.4 4.1 5.1 6.2 7.5 9.2 11.2

2.2.7 The insulation resistances of oil submerged pumps and fan motors should be measured by 500V megger before they are put into operation after a overhaul and a minor repair of forced air cooling transformer and oil immersed air cooling transformer. The insulation resistance value should not be less than 0.5 megohm.

2.3 Manual for Normal Operation Voltage of Transformer

2.3.1 The transformer should comply with the voltage value specified on the nameplate in normal operation. The rated capacity of transformer will not change when the voltage changes in ±5% of relevant tap voltage.

2.3.2 The maximum voltage applied on each tap must not exceed 105% of rated voltage of relevant tap. When the voltage drops to below 95% rated value, the capacity should be decreased and the limitation is the rated current not to exceed 105% rated value.

2.3.3 As for a no-load voltage regulating transformer, it is prohibited to change the position of HV tap changer, if the voltage in the load side of transformer is too high or too low, the position of HV tap changer needs to change, the maintenance personnel will be informed to carry out change after the power supply of transformer is cut off and released from the standby state and the safety measures are completed; the transformer can be put into operation after the switchover is completed and DC resistances are measured up to standard.

2.4 Operation Instructions for Voltage Regulating Device

2.4.1 Operation Instructions for No-load Regulating Device

A no-load tap changer must be used for changing tap when the transformer does not carry load, it must be confirmed that the transformer is in power cut state prior to operation.

When a tap is changed, a set screw is at first unscrewed on the hand lever housing, and then the hand lever housing is moved to make finger aligning to the tap position required, the set screw is tightened again. If taps for no-load voltage regulating transformer have not been adjusted over a long period of time, the tap changer should be backwards and forwards turned several times for changing tap, and then adjusted to the tap required, finally the set screw is tightened.

2.4.2 Operation Manual for On-load Voltage Regulating Tap Changer of Main Transformer and Startup Standby Transformer

The on-load voltage regulating devices of main transformer and startup standby transformer are provided with two operating modes: the normal adjustment will be operated by electric remote control in remote, and it can be operated by electric control in local when the remote control is in malfunction.


- 47 -

A principle of step-by-step rise and fall should be complied with during the operation of on-load voltage regulating device, and it is to keep watch the remote indication of position indicator is consistent with the local indication. No matter whether the position of tap changer in the HV side is to rise or fall, the rise or fall operation can be carried out after the figure of position indication on tap changer in the HV side has not changed and after it is checked that the voltage of 6kV busbar or the generator terminal voltage is steady and the current is normal.

If the electric operating mechanism of on-load voltage regulating device is rising or falling without cease, the emergency button should be rapidly pressed to cut off the operating power supply of on-load voltage regulating device; the operating power supply of on-load voltage regulating device can be switched on at local after it is treated and in normal condition.

It is strictly prohibited to carry out switchover operation of taps when the main transformer and the startup standby transformer are in serious overload state or there is any fault with the power grid system.

2.5 Parallel Operation of Transformers

2.5.1 The parallel operation of transformers should meet the following conditions:

Phase sequences are same.

Connection symbols are same.

Voltage ratios are same (5% difference is permissible)

The short circuit impedances are same (5% difference is permissible). Transformers with same voltage ratio and different short circuit impedance can operate in parallel under the condition of any one of transformers not to operate with overload. When transformers with different short circuit impedances operate in parallel, the secondary voltage of transformer with higher short circuit impedance should be properly increased so as to fully utilize the capacities of two transformers.

The capacity ratio is not more than 3:1.

2.5.2 If the disorder of phase sequence is likely to arise due to the causes such as newly installation or overhaul of transformer, the phase sequence and phases should be measured before paralleling or loop closing operation.

2.5.3 The parallel on and off of transformer should be completed by a circuit breaker. Any knife switch must not be used for putting a transformer into or out of operation.

2.6 Manual for Overload Operation of Transformer

2.6.1 A transformer is permitted to operate under the conditions of normal overload and accident overload. It can often operate with normal overload, and the permissible overload time will be executed as specified; it can only operate with accident overload under an accident condition; the operation states of the transformer should be closely monitored during the overload operation.

2.6.2 A transformer must not operate with normal overload under the following conditions:

There are defects existed in a transformer, for example: oil leakage, local overheat phenomenon, weak point existed in insulation etc.

A transformer always operates with full load.

Coolers of a transformer can not be totally put into operation.

2.6.3 The overload of main transformer should correspond with the permissible overload of generator, in which the stricter one will act as operation basis. The permissible operation time for accident overload of main transformer is executed as per the following table (in hour):

Multiple of overload

Upper layer oil temperature before overload (℃) 0 10 20 30 40


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1.10 24：00 24：00 24：00 14：30 5：10 1.20 24：00 21：00 8：00 3：30 1：35 1.30 11：00 5：10 2：45 1：30 0：45 1.40 3：45 2：10 1：20 0：45 0：15 1.50 1：50 1：10 0：40 0：16 0：07 1.60 1：00 0：35 0：16 0：08 0：05 1.70 0：30 0：15 0：09 0：05 0

2.6.4 Overload and permissible operation time of HV auxiliary power transformer are executed as per the following table

Multiple of overcurrent 1.2 1.3 1.45 1.6 1.75 2.0 Permissible operation time (min) 480 120 60 45 20 10

2.6.5 Overload and permissible operation time of LV auxiliary power transformer are executed as per the following table

Overload current /rated current 1.2 1.3 1.4 1.5 1.6 Duration time of overload (min) 60 45 32 18 5

2.6.6 All coolers of a transformer should be totally put into operation in the case of the transformer operating with normal load and accident load.

2.6.7 The values and the duration time of overload should be recorded and closely monitored when a transformer operates with overload; when the upper layer oil temperature or the winding temperature reach the maximum permissible value, no matter whether the multiple and the duration of overload reach the specified values, the overload operation of generator should be stopped to prevent damage accident of transformer.

2.7 Operation of Transformer Cooling Device

2.7.1 Operation of main transformer Cooling Device

The main transformer adopts forced oil circulation air cooling mode. The coolers of main transformer should be put into operation as specified before the main transformer is put into operation, and the cooling device must be guaranteed to reliably operate during the main transformer operates.

There are two power supplies for the forced oil circulation air cooling of main transformer, which are separately fed from 380V unit section A and B of each unit.

The automatic putting into operation of cooling power supply of main transformer is controlled by the circuit breaker in the HV side of main transformer. The power supply of coolers will put into or out of operation along with closing and opening of HV side circuit breaker when the automatic mode is selected (“1K” switch is placed in “Auto” position): the corresponding quantity of “Working” coolers preselected can be automatically put into operation while the main transformer is put into operation in the power grid; all coolers putting into operation can be automatically switch off when the main transformer is switch off. In general, manual mode is selected (“1K” switch is placed in “Manual” position).

The whole cooler system is equipped with two independent power supplies, one can selected as working power supply and another can selected as standby power supply in the two power supplies which can automatically change over (“I Work” and “II Work” selected by a changeover switch). The standby power supply will automatically put into operation when the working power supply is in malfunction; the standby power supply will be automatically out of operation when the working power supply resumes; the load of AC contactor can be relieved when two power supplies are operating to form sectionalized busbar operation; when any working power supply is


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out of operation due to a fault, the power supply can be automatically changed over to put the busbar tie contactor into operation and guarantee continuous operation of the coolers.

The protection elements of oil pumps and fan motors of coolers can effectively prevent oil pumps and fans from damages resulting from open phase, loss phase, short circuit and three phases power supply unbalance etc.

2.7.2 Temperature Protection Device of Transformer

The main transformer body is equipped with two sets of signal thermometers and two sets of winding thermometers. The preset temperature of signal thermometer control switch K1 is 45℃ which is used for switching off the auxiliary coolers; the preset temperature of control switch K2 is 60℃ which is used for switching on auxiliary coolers; the preset temperature of control switch K3 is 85℃ which is used for signal alarm; the preset temperature of control switch K4 is 100℃ which is used for trip. The preset temperature of winding thermometer control switch K1 is 65℃ which is used for switching off auxiliary coolers; the preset temperature of control switch K2 is 80℃ which is used for switching on auxiliary coolers; the preset temperature of control switch K3 is 100℃ which is used for signal alarm; the preset temperature of control switch K4 is 110℃ which is used for trip.

The HV auxiliary power transformer body is equipped with two sets of signal thermometers and one set of winding thermometer. The preset temperature of signal thermometer control switch K1 is 45℃ which is used for switching off fans; the preset temperature of control switch K2 is 60℃ which is used for switching on fans; the preset temperature of control switch K3 is 90℃ which is used for signal alarm; the preset temperature of control switch K4 is 100℃ which is used for trip. The preset temperature of winding thermometer control switch K1 is 70℃ which is used for switching off fans; the preset temperature of control switch K2 is 80℃ which is used for switching on fans; the preset temperature of control switch K3 is 100℃ which is used for signal alarm; the preset temperature of control switch K4 is 110℃ which is used for trip.

The startup standby transformer body is equipped with two sets of signal thermometers and one set of winding thermometer. The preset temperature of signal thermometer control switch K1 is 55℃ which is used for switching off fans; the preset temperature of control switch K2 is 65℃ which is used for switching on fans; the preset temperature of control switch K3 is 80℃ which is used for signal alarm; the preset temperature of control switch K4 is 90℃ which is used for trip. The preset temperature of winding thermometer control switch K1 is 70℃ which is used for switching off fans; the preset temperature of control switch K2 is 80℃ which is used for switching on fans; the preset temperature of control switch K3 is 90℃ which is used for signal alarm; the preset temperature of control switch K4 is 100℃ which is used for trip. The fans will not be started up below 70% capacity and the natural oil circulation cooling is used.

2.8 Operation Manual of Transformer Gas Protection

The valve on the connecting pipe of gas relay should be in open position.

The vent line of gas relay should be in normal working state.

There should be no gas in the gas relay.

The transformer gas protection is set in trip position in normal operation. If it is necessary to disable the gas protection due to working needs when the transformer is in operation, it must be approved by a leader in charge of production and reported to the dispatchers, and it is strictly prohibited that other main protections of transformer are out of operation.

The trip strap of gas protection should be put into operation when a transformer is to put into operation and charge after it is newly installed or goes through overhaul, the trip strap of gas protection will be out of operation after the transformer is charged to achieve normal condition.


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The air in inside of the transformer will be exhausted after it is charged to normally operate for 48 hours, and the trip strap of gas protection should be put into operation.

The trip strap of gas protection should be out of operation during operation of transformer under the following conditions, and then the relevant treatments will be carried out:

a). The trip strap of gas protection should be out of operation when oiling and filtering oil of transformer are being carried out; and it can be put into operation after the workings are finished and the transformer operates for 48 hours, and inner air has been exhausted.

b). There is work with breather and bursting diaphragm, and the silica gel of oil regenerator is replaced.

c). The oil circuit part of coolers will be repaired.

d). When the oil level indicated on the transformer oil level gauge unconventionally rises or there is abnormal phenomenon occurred in the oil circuit system, it is necessary to open each vent or oil drain plug and valve, and check moisture absorber or carry out other work in order to find out the causes, then the trip strap of gas protection must be out of operation, and it can be put into operation after all work are finished and air in the inside of the transformer has been exhausted.

e). When there is any work on the secondary circuits of transformer gas protection (such as verify check of gas relay, treatment of DC circuit fault etc.), the transformer gas protection will be out of operation, and the heavy gas protection is changed to signal, it can be set to trip after all work are finished.

f). The valve on the connecting pipe of gas relay is opened and closed.

It is strictly prohibited the trip strap of gas protection is out of operation when the oil level falls (oil leakage, oil impregnate) to result in light gas signal to be send out.

2.9 Manual for Neutral Point Earthing of Startup Standby Transformer

2.9.1 Operation of Startup Standby Transformer Neutral Point

The neutral point earthing knife switch must be closed before the circuit breaker of startup standby transformer is closed or opened. If the startup standby transformer is to charge as standby, the neutral point earthing knife switch should be opened after the startup standby transformer is charged to achieve the normal condition.

When the startup standby transformer acts as interlock standby, the neutral point earthing knife switch of startup standby transformer must be closed. The neutral point earthing knife switch of startup standby transformer should be opened after the circuit breaker of startup standby transformer acts by interlock.

2.10 Neutral point earthing resistance cabinet of HV auxiliary power transformer, startup standby transformer

Insulation Manual of Resistance Cabinet

It is to measure the insulation resistance of primary circuit. The connecting wire is removed between the tail end of the resistance and the top porcelain insulator of earthing cable, and the insulation resistance measured by 2500V megameter should more than 1000 MΩ.

Current Transformer of Resistance Cabinet

There are 2 current transformer installed in the bottom of resistance cabinet, 1LH is used for protection circuit in the control box, and 2LH is used for user’s protections and measurements.

Startup of Resistance Cabinet Fan

The faceplate of control box is located in the lower side of cabinet, when the switch K1 is changed over to “Manual” position, the fan can be started up or stopped by pressing pushbutton “STARTUP” and “STOP”; when the switch K1 is changed over to “AUTO” position, the fan is in


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standby state. When an earthing fault occurs in the 6kV system, the current passed through the earthing resistance is more than the set point of current relay, LJ acts and the fan will automatically start up. The earthing current of resistance cabinet earthed can be eliminated after 6kV earthing fault is eliminated or the main circuit breaker of power supply in the relevant side of transformer trips. LJ overload relay reset, the time relay of the control box starts up. The fan is continuously operating for a delay time to remove the remaining heat in the control box. The fan can automatically stop operation and is in standby state after the delay setting value is reached.

The maintenance of resistance cabinet can be carried out only after the transformer is in power cut.

3 Checks and Tests of Transformer 3.1 Checks and Tests before Transformer Putting into Operation

All maintenance work permits are taken back. All short circuit wires and earthing cables should be removed in the primary circuit, all earthing knife switches should be opened, all standing fences and nameplates are set up as specified, doors of transformer rooms are locked and are provided with good illumination.

There is no short circuit and earthing phenomenon in the primary circuit and the phase sequence is correct.

The equipment markings and symbols should be visible and correct.

Oil color, oil level and oil temperature in the oil conservator and bushing should be normal without oil impregnate and oil leakage.

The stop valves of gas relay, radiator and oil regenerator should be opened.

Check that HV and LV bushings are in good condition, the transformer pressure release device is complete and the breather silica gel color is normal. All connections of lead wires, busbars and bushings of transformer should be tight and in good condition.

The position of tap changer is correct, and the regulating device of on-load voltage regulating tap changer should be complete and flexible.

All insulations measured for all parts of transformer are qualified. The insulations can not be measured when the outage time of outdoor transformer does not excess 48 hours, and the outage time of indoor transformer does not excess 15 days, and there is no reason to possibly reduce insulation to be found. But checks must be carefully carried out. The insulations must be measured after an overhaul of transformer is finished.

As for a unit wiring transformer which can not be separated with the generator, the insulations of this transformer can be measured along with the generator, but short circuit and earthing should be applied in the HV side of the transformer before measurement in order to avoid the effect of induced voltage in the HV side. If the measurement results do not conform to the specified requirements, the measurement will be carried out after the transformer is separated from the generator; the transformer can be put into operation only after the reasons have been found out and it resumes to normal condition.

There is no hangover on the top and the current carrying part of transformer.

The earthing cable of transformer shell is in good condition.

The power supply of cooling device is in good condition.

The motor of cooling device is normally running, and there is no abnormity of the signal and electrical elements in the cooler control box.

The inlet and outlet oil butterfly valves of each set of cooler are in open position.

The rotation direction of oil submerged pump is correct and there is no abnormal sound and obvious vibration in the operation, the temperature rise of motor is normal, and the action of oil


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flow relay is normal.

The cooling device of transformer should be put into operation before the transformer is put into operation. All cooling devices of forced oil circulation cooling transformer should be put into operation to remove residual air before the transformer is put into operation after overhaul, repair of cooling device, oil replacing, oil filtering of the transformer. The auxiliary coolers and standby coolers will be stopped as specified after 1 hour.

All relay protection devices, control circuits and straps and miniature switches of a transformer should conform to the operation requirements. The transformer protections should be put into operation in accordance with the commands of dispatchers.

There should be written instructions for putting the transformer into operation after a transformer overhaul is carried out.

It is to be checked the ventilation is good in LV auxiliary power transformer room; there are measures for preventing foreign matters entry at air inlet and outlet of transformer cabinet.

Check whether the indications for oil thermometers and winding thermometers of transformer body conform to the actual condition, and the indications will be check against BTG panel / CAT values.

There is no other factor threatening the safety operation of transformer.

3.2 Check of Transformer in Operation

Oil level and oil color of transformer should be normal without oil impregnate and oil leakage in all parts.

Transformer sound should be normal in operation, and there is no noise and discharge sound in the inside of transformer.

Transformer oil indication is normal, and the temperature rise is in the specified range.

The radiator, breather, oil regenerating device normally operate, and the pressure relief valve is normal.

The bushings are complete without flashover discharge phenomenon.

The oil level of gas relay is normal, the connecting oil valve is in open state, and there is no air in the gas relay.

There is no severe vibration with fans and oil pumps in operation; there is no abnormal sound and overheat phenomenon with motors; the rotary speed is normal; and the oil flow relay operates normally.

There is no overheat phenomenon with the all lead-in connection cables and busbars, and there is no oil leakage with cables.

There is no overheat in all parts in the control box of cooling device, and all hand level positions conform to the requirements of operation mode.

The doors and windows in transformer rooms are complete, the ventilation is good, the lighting is normal, the fire fighting devices are complete, there is no water leakage in the room and the room temperature is normal.

The ventilation is good in the dry transformer cabinet, and there is no hot air detained in the space on the top of transformer.

3.3 Special Check of Transformer

The lead wire should not acutely swing in strong wind, the transformer bushings should not loose and there is no foreign matter on the top cover and in surrounding

The oil level change and the operation of cooling device should be checked when the air temperature is very cold and very hot.


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It should be checked that there is no flashover discharge on all parts and there is no die burn, rupture trace after heaven fog and thunder storm.

The snow melting should be checked in heavy snow to judge whether there is overheat, and Check whether there is any icicle to be likely to give rise to flashover on porcelain insulator.

A light-off check should be carried out at night there is no any heating and red-hot phenomena with all connections, and there is no discharge phenomena with bushings.

The transformer body should be immediately checked after the gas relay acts.

3.4 Check Items for Dry Transformer

The temperature measuring devices of transformer are in good condition, and the temperature indications are normal.

Shell temperature, color, smell, noise and vibration of transformer are normal.

The transformer cooling fans are normally operating.

The front and rear door sheets and fences of transformer are in good condition.

There is no dirt retention on the outside surface of transformer.

There is no water leakage or other abnormal phenomena of endangering safety around transformer.

The transformer, which is put into operation after newly installation or overhaul, should be checked once every hour in 3 hours after putting into operation; and then the check times should be properly increased in 72 hours after putting into operation; finally the normal check will be resumed.

Patrol check and check times should be increased when there is any defect in the transformer and in high temperature season and during peak load; the operation state of transformer should be uninterruptedly monitored and checked.

4 Transformer Putting In or Out of Operation 4.1 Transformer Putting Into Operation

4.1.1 Checks should be carried out as specified in clause 2.3.1 before a transformer puts into operation.

4.1.2 Closing and tripping test of circuit breaker should be normal before a transformer puts into operation; protection transmission test should be carried out and be normal when there is working in the protection circuits.

4.1.3 The circuit breaker in the power supply side (normally it is HV side) should be closed at first, and then the circuit breaker in the load side (normally it is LV side) when a transformer is to put into operation.

4.1.4 A transformer newly installed or after overhaul should carry out impact closing test in accordance with the following conditions:

All protections of the transformer are set to trip.

The neutral point earthing knife switch of the transformer must be closed in the neutral point earthing system when the impact closing is carried out.

Full voltage impact closing can be carried out when the transformer is first put into operation, and the circuit breaker in the power supply side of transformer is used when the impact closing is carried out.

The first power-on duration of the transformer should not be less than 10 minutes, it is to be checked there is no abnormity.

The transformer should carry out 3 times of impact closings without abnormity (each interval is 5 minutes); the excitation surge current should not lead to action of protections.


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It should be checked the phase sequence and phase position are coincident and conform to the parallel operation conditions to prevent the auxiliary power transformer seriously exceeding rated current before the transformer parallels on.

All parts should be checked to operate in good condition after the transformer is in power on.

4.2 Transformer Out of Operation

4.2.1 The load carried by the transformer should be transferred or stopped in advance in accordance with the unit operation conditions before the transformer power cut.

4.2.2 The circuit breaker in the load side should be switched off at first, and then the circuit breaker in the power supply side can be switched off when the transformer power cut.

4.2.3 The circuit breaker in the LV side should be switched off at first, and then the circuit breaker in the HV side can be switched off when a LV auxiliary power transformer is out of operation.

4.2.4 Safety measures are arranged in accordance with the tasks and working requirements of overhaul.

5 Abnormal Operation and Accident Handling of Transformer 5.1 A transformer must immediately stop operating when the transformer occurs one of the

following conditions.

There is very big and abnormal noise and explosive sound in the inside of the transformer.

The transformer temperature abnormally and continuously rises under a normal load and cooling condition.

Oil spouts out from conservator and pressure releaser.

The oil level falls due to serious leakage, and lower than the lower limit of oil level gauge.

Oil color changes greatly, carbon occurs in oil.

There is serious damage and discharge phenomenon on bushings.

Lead wire terminal burns.

Transformer catches fire.

5.2 When a transformer takes place one of the following conditions, it is permitted to outage after reporting; if the condition is permissible, the standby transformer can be changed over.

There is abnormal sound in the transformer and there is ascending trend, but there is no discharge sound.

Insulation oil becomes dark colored, cloudy, and viscosity and acidity are increased after chemical examinations.

Cracks and oil impregnate appears on bushings, there are discharge phenomenon and discharge trace.

Cracks of aluminum busbar, broken strand of lead wire or heating and discoloration of lead wire terminal occur.

There are serious oil leakages in cooler and oil valve gland packing as well as welding zone of oil pipe.

There is foreign matter endangering safety on the top of transformer and they can not be removed without power cut.

The transformer oil temperature and winding temperature abnormally rise while the transformer load, ambient temperature and cooling conditions do not change.

The on-load voltage regulating device is in malfunction which can not be handled without power cut.

All main protections of transformer are out of operation.


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5.3 Transformer Overload

If a overload of the main transformer occurs, it is reported to the dispatchers and the load is to be limited; when the permissible overload duration time and the permissible sundries of a LV auxiliary power transformer are exceeded, the load can be transferred; if the overload results from the external short circuit, it is a short circuit overload and the fault should be rapidly cut off. The overload duration time for main transformer, HV auxiliary power transformer, HV standby transformer, LV auxiliary power transformer will be executed as specified in this Manual, meanwhile, it is to be paid attention to and checked the transformer cooling system normally operates.

5.4 Transformer Temperature High

5.4.1 Oil Immersed Transformer Temperature High

Check the local thermometer and compare with DCS parameters, if the temperature measured point is not normal, the maintenance personnel should be immediately informed to handle.

Check whether the operation of transformer cooling system is normal, and the standby coolers are properly started up to reduce the oil temperature.

Immediately check the load of transformer, and synthetically analyze the reasons of “High Oil Temperature”, and go to the field to check the transformer body, verify whether or not the “High Oil Temperature” alarm is correct.

When it is confirmed that the transformer temperature is abnormal rise, the transformer load should be properly reduced and the oil temperature change should be observed.

If the transformer oil temperature continuously rises after the abovementioned measures are taken, the load should be immediately switched over to other transformer, and the operation of transformer will be stopped, and it should be reported to the shift supervisor.

If the upper layer oil temperature of main transformer exceeds 75℃, and the upper layer oil temperature of HV standby transformer and the HV auxiliary power transformer exceeds 95℃, the conditions should be immediately reported to the shift supervisor.

5.4.2 Dry Transformer Temperature High

Go to the transformer body to check, and verify the “High Temperature” alarm is correct.

Check whether the ventilation is good in the transformer cabinet, whether or not the cooling fans of transformer is automatically started up, whether or not the intake is blocked up and ensure the ventilation is in good condition in the transformer cabinet.

Examine whether or not the high temperature results from the indoor temperature to be high, if yes, the indoor ventilating fans should be started up to keep good ventilation.

If it results from the heavy load of transformer, the load of this transformer should be transferred and reduced so as to reduce the temperature.

If the temperature is abnormal rise or it is doubted that the transformer exists fault, the load should be transferred to other transformers, the operation of this transformer should be stopped.

5.5 Handling for Transformer Gas Protection Action

5.5.1 Causes and handling of “Transformer Light Gas” Signal Send out

5.5.1.1 In general, there are following causes for light gas protection action:

Due to oil filtering, oil filling or cooling systems are not tight, air invades in the transformer.

Due to the temperature decreases or oil leakage, the oil level falls to below the lower limit.

Due to transformer fault, a small quantity of gas is generated.

Due to secondary circuit fault, signal is falsely send out.


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5.5.1.2 Solution

It is reported to the shift supervisor, and check whether the transformer oil level is normal, whether or not there is any oil leakage, whether or not there is any rupture and oil injection phenomena on the explosion stack and bushings, whether or not the pressure relief valve acts.

Check whether there is any earthing in the DC system and there is any fault in the secondary circuits (for example, the insulation of lead wire of gas relay is not undesirable).

The operation of the transformer should be closely monitored, for example, changes in current, voltage and sound etc. and the transformer load should be properly reduced, at this moment, the heavy gas protection must not be out of operation.

Check whether there is any gas in the gas relay, if yes, the chemical personnel should be informed to sample for analysis, the gas color will be observed and the gas bleeding and ignition test will be carried out, the sampling will be executed in accordance with the working requirements in “Safety Manual”; if the gas is flammable or yellow, it proves it is oil quality or insulation fault, and the results are reported to the shift supervisor and an application for transformer outage will be filed.

If the intervals between two consecutive signals send out gradually shorten, it should be reported to the relevant leaders, and transformer should be switched over, and the transformer with fault should be stopped to inspect in detail.

If the heavy gas protection is set to the signal position and the action signal is send out (there is drop), transformer should be immediately switched over, and the fault transformer should be stopped; when the signal sends out and it is found that the transformer current is abnormal at the same time, this transformer should be immediately stopped.

5.5.2 Handling for Gas Protection Action to Trip

As for main transformer and HV auxiliary power transformer, it will be handled as per the generator-transformer unit accident handling Manual: check whether the standby power supply has been put into operation, if not, check the LV side circuit breaker of HV auxiliary power transformer has been reliably opened, if there is no lock signal of quick switchover device, the standby power supply can be forcedly put into operation one time to ensure the normal power supply of the auxiliary power system. If the standby power supply putting into operation is unsuccessful, it is prohibited to put into operation again.

Check whether the temperature and oil level of the transformer tripped are normal, and there is any oil injection on explosion stack and other position.

A gas sample chromatoraphic analysis and oil quality chemical examination as well as oil withstand voltage test will be carried out, if there is any problem to be found, the transformer must not be put into operation.

If there is no problem to be found after the abovementioned check, analysis, chemical examination, the maintenance personnel should inspect the gas protection and its DC secondary circuit. If it is confirmed the gas protection is false action, the gas protection will be out of operation, the maintenance personnel will inspect the reasons of false action, other main protection of the transformer will be put into operation and the operation of this transformer resumes.

If the gas protection and differential protection act at the same time, and there is flammable gas by checking, the transformer is forbidden to put into operation without test to be qualified.

The gas protection acts to trip, if it is verified it is caused by human error, the transformer can be put into operation at once after there is no abnormity by appearance inspection.

5.6 Handling for Transformer Differential Protection Action

5.6.1 The transformer can not be forcedly power on after the differential protection acts; the standby


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transformer can be put into operation when there is a standby transformer.

5.6.2 If the differential protection acts, and the gas protection of this transformer acts at the same time, there is impact to the power grid system or obvious fault phenomenon is found by inspecting, the transformer should be power cut, and further inspections and treatments will be carried out.

5.6.3 If the differential protection acts, there is no impact to the power grid system, and the gas protection does not act, the equipments in the protection range should be checked, if there is any abnormity to be found, it will be treated as per the following principles.

The relay persons are informed to inspect the differential protection and secondary circuits, if it is false action or there is any problem in the secondary circuits, the differential protection should be out of operation, whether or not the transformer putting into operation is decided by the chief engineer.

If there is no problem to be found by inspecting, after the transformer insulations are measured and the direct current resistances are normal, and the chief engineer approves, the transformer voltage can be raised from zero, and it must make sure the three phase currents should be zero; it should remain one minute when the voltage is raised to 105% rated voltage, and then the voltage falls to the rated value after it is checked there is no abnormity, and the transformer has been put into operation over again. If the transformer voltage can not be raised from zero, the transformer can be charged one time after approved by the chief engineer, it can be put into operation after the charge is normal.

5.6.4 If the trip results from human error, the transformer can be put into operation without inspection.

5.7 Handling for Transformer Overcurrent Protection Action

5.7.1 If HV auxiliary power transformer branch overcurrent, compound overcurrent section I, standby branch overcurrent protections act, no matter whether MFC (quick switchover device of auxiliary power) acts, this 6kV busbar section must not be power on. This busbar can be power on only after the 6kV busbar fault has been eliminated or the load which results in the trip by skipping a grade has been isolated, and the insulations are measured up to standard.

5.7.2 If the instantaneous current protection of an auxiliary power transformer trips, no matter whether the standby power putting into operation is successful by interlock or manual operation, the working transformer must not be forcedly put into operation.

5.8 A Mass of Oil Leakage of Transformer

Transformer is immediately switched over, and it should be informed to the maintenance personnel to handle.

Main transformer obviously leaks, it should be informed to the maintenance personnel to supplement oil or handle.

Oil leaks due to cooler broken, measures should be taken to handle as soon as possible.

If there is no effect after handling, it should be reported to the shift supervisor to stop the fault transformer.

5.9 Handling for Transformer Catching Fire

All sides of power supplies should be rapidly switched off.

The standby transformer is put into operation.

The cooling device of the transformer is stopped.

If the fire is on the top of transformer, the oil drain valve should be opened to discharge oil, and the oil level is lower than the fire level. If the fire is caused by the inside fault of transformer, the oil can not be discharged to prevent explosion of transformer.

The fire fighting will be carried out in accordance with the fire fighting Manual, it is informed to the fire department and reported to the relevant leaders.


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If a mass of oil leaks due to the explosion stack bursts or the pressure releaser acts for large scale of transformer, the fire fighters should keep away from the transformer in order to prevent explosion of the transformer.


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Chapter IV Distribution Device Manual 1 Equipment Specification of Distribution Devices 1.1 Technical Parameters of HV Sulfur Hexafluoride Circuit Breaker for ZF9-252/Y4000-50 Gas

Insulation Metal Enclosed Switchgear (GIS)

No. Item Unit Technical Parameter 1 Rated voltage kV 252 2 Rated frequency Hz 50 3 Rated current A 3150

4 Rated short circuit breaking currentIK

Short circuit current kA 50

Direct current component percent - 50%

5 Rated short-time withstand current（4s） kA 50 6 Rated peak withstand current (peak value) kA 125 7 Rated short-time closing current (peak value) kA 125 8 Near zone fault breaking current kA IK×90%; IK×75% 9 Out-of-step breaking current kA IK×25%

10 Rated line charging breaking current A 160 11 First pole to clear factor — 1.5 12 Rated operation sequence — O-0.3s-CO-180s-CO 13 Breaking time ms ≤50 14 Rated opening time ms ≤25 15 Rated closing time ms ≤100

16 Close-open time ms >40（guaranteed by user）

17 Open-close time ms 300 18 Inter-pole closing synchronism ms ≤4 19 Inter-pole opening synchronism ms ≤2 20 Quantity of fractures for each pole Pcs. 1

21 Operating mode — Split pole operating or three poles electrical interlock

22 Main circuit resistance of each pole μΩ ≤60 23 Radio disturbance voltage μV ≤500 24 Mechanical life times 5000

25 Electrical life under the rated short circuit breaking current times 20

26 Rated SF6 gas pressure (20℃) MPa 0.5 27 Permissible yearly leakage rate of SF6 gas — ≤0.5%

28 Water content of SF6 gas

Acceptance value ppm (V/V)

150 Permissible operation value 300

29 Operating mechanism used - CYA3-Ⅱ type hydraulic spring operating mechanism

30 Reference standard - GB1984 and IEC60056


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1.2 Rated Insulation Level

No. Designation Unit Parameter

1 1min power frequency withstand voltage (effective value)

Dry, wet

Between fractures kV

395+145

Against ground 460

2 Rated lightning impact withstand voltage (peak value)

Between fractures kV

950+206

Against ground 1050

3 5min zero gauge pressure power frequency withstand voltage (effective value)

Between fractures

kV

1.3×252/ 3 Against ground 1.3×252/ 3

4 1min power frequency withstand voltage of auxiliary circuits 2

5 1min interturn withstand voltage AC of opening and closing coil V 2.5×220/110

1.3 SF6 Pressure Parameters (at 20℃)

No. Item Unit Technical Parameter 1 Rated pressure MPa 0.50 2 Gas filling alarm pressure MPa A=0.45±0.03 3 Gas filling alarm release pressure MPa A1=A+（0.010.05） 4 Circuit breaker lock pressure MPa L=0.40±0.03 5 Circuit breaker lock release pressure MPa L1=L+（0.010.05）

1.4 Parameters of Control Circuits and Auxiliary Circuits

No. Item Unit Data Remarks

1 Control voltage of opening and closing coil V DC110/220

2 Opening coil current A 3.06/1.43 3 Closing coil current A 3.06/1.43 4 Supply voltage of motor V DC220/AC220 5 Power of motor W 660

-- 6 Heater Voltage V AC220 Power W 100

1.5 Technical Parameters of ZF9-252/Y4000-50 GIS Isolating switch

1 Rated voltage kV 220 2 Rated current A 3150 3 Rated frequency HZ 50

4 Rated short-time withstand current (effective value) kA 50（3 s）

5 Rated peak withstand current (peak value) kA 100

6 Rated power frequency withstand voltage (effective value) kV 460 1min

7 Rated lightning impact withstand voltage (peak value) kV 1050

8 Rated SF6 filling pressure (20℃) MPa 0.4 9 SF6 leakage rate % year ≤1

10 Insulation level Rated power frequency withstand voltage (effective value) kV Against ground 460 1min


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Rated lightning impact withstand voltage (peak value) kV Against ground 1050

11 Model of operating mechanism Electric 12 Mechanical life times 3000 13 Rated control voltage V DC110 14 Rated voltage of motor V AC220 15 Voltage of Heater V AC220

1.6 Technical Parameters of Overhaul Earthing Switch Used for ZF9-252/Y4000-50 GIS

No. Item Unit Technical Parameter 1 Rated voltage kV 220 2 Rated frequency HZ 50

3 Rated short-time withstand current (effective value) kA 50 （3 s）


5 Rated power frequency withstand voltage (effective value) kV 460 1min

6 Rated lightning impact withstand voltage (peak value) kV 1050

7 Rated SF6 filling pressure (20℃) MPa 0.4 8 SF6 leakage rate %year ≤1

9

Insulation level Rated power frequency withstand voltage (effective value) kV Against ground 460 1min


10 Model of operating mechanism Electric 11 Mechanical life Times 3000 12 Rated control voltage V DC110 13 Rated voltage of motor V AC220 14 Voltage of Heater V AC220

1.7 Technical Parameters of Fault Closing Earthing Switch Used for ZF9-252/Y4000-50 GIS

No. Item Unit Technical Parameter 1 Rated voltage kV 220 2 Rated frequency HZ 50

3 Rated short-time withstand current (effective value) kA 40 （3 s）


5 Rated power frequency withstand voltage (effective value) kV Against ground 460 1min

6 Rated lightning impact withstand voltage (peak value) kV Against ground 1050

7 Rated SF6 filling pressure (20℃) MPa 0.4 8 SF6 leakage rate % year ≤1

9

Insulation level Rated power frequency withstand voltage (effective value) kV Against ground 460 1min


10 Model of operating mechanism Electric spring 11 Mechanical life times 3000 12 Rated control voltage V DC110 13 Rated voltage of motor V AC220


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14 Voltage of Heater V AC220

1.8 BANTEN 2×300MW CFSPP Station

The main busbar adopts three phases integrated box type structure, and the branch busbar adopts three phases split box type structure, and the parameter are as follows:

Rated frequency 50Hz

Rated voltage 220kV。

Rated current 4000/3150A。

Rated short-time withstand current（3s） 50kA。

Rated lightning impact withstand voltage (peak value) 1050 kV。

Rated short-time power frequency withstand voltage (1min effective value)

Voltage against ground 460kV。

Rated SF6 gas pressure 0.40MPa.

1.9 Technical Parameters of Voltage Transformer JDQX8-150ZHA1

Maximum voltage of equipment 170kV

Rated primary voltage 150/ 3kV

Rated secondary voltage a）0.1/ 3kV; 0.1/ 3kV; 0.1 kV.

b）0.1/ 3kV; 0.1/ 3kV; 0.1/ 3kV; 0.1 kV.

Accuracy class combination a)0.2/0.5/3P.

c)0.2/0.5/3P/3P.

Rated output a)100/100/100 VA

d) 50/100/100/50 VA

1.10 Technical Parameters of Enclosed Busbar

Model: QLFM- 24/12500 Rated voltage（KV） 24KV Maximum working voltage（KV） 27.6KV Ambient temperature: -40℃ to +40℃ Altitude: ≤1000m Earthquake intensity: 8 degree Permissible temperature of maximum hot point of busbar conductor 50K

Permissible temperature rise of maximum hot point of shell: 30K

Temperature rise of maximum hot point of conductor contact surface (contact surface silvered) connected by bolts: 60K

Dimension of busbar conductor Ф1050 Dimension of busbar shell: Ф500 Distance between phases: L=1400mm

1.11 Micro Positive Pressure Device of Enclosed Busbar

Rated input air pressure （5~7）×100 kPa Air pressure in busbar shell 500～2500Pa Rated air filling flow 35m3 / h


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1.12 Technical Parameters of Branch Circuit Enclosed Busbar

Model: QLFM- 24/1600 Rated voltage（KV） 24KV Maximum working voltage（KV） 27.6KV Ambient temperature: -40℃～+40℃ Altitude: ≤1000m Earthquake intensity: 8 degree Permissible temperature of maximum hot point of busbar conductor

50K

Permissible temperature rise of maximum hot point of shell:

30K

Temperature rise of maximum hot point of conductor contact surface (contact surface silvered) connected by bolts:

60K

Dimension of busbar conductor Ф700 Dimension of busbar shell: Ф150 Distance between phases: L=1000mm

1.13 Detailed Parameters of Micro Positive Pressure system

1) Dryness of output air (outlet dew temperature):

2) Outlet air pressure: 300Pa –2500Pa

3) Outlet pressure of air compressor: 0.4Mpa-0.7Mpa

4) Pipe diameter of air inlet: G1/2〞, pipe dimension of air supply opening: G1/2〞

5) Power supply: AC380V 50Hz (three-phase four-wire system)

6) External dimensions 800(W) ×1200（H）X600(L)

1.14 Excitation transformer, generator neutral point grounding transformer, risistance and current transformer

Model number ZSCB9-3600/20 DC-35/20/0.22 ZX-20 LZZBJ9-10C20

Type Dry type excitation transformer

Generater neutral point grounding

transformer

Generater neutral point grounding resistance

Generater neutral point grounding

current transformer

Cooling mode AN AN Rated frequency 50Hz 50HZ 50HZ Rated capacity 3600kVA 35KVA 55KW 30VA

Code of the connecting unit Yd11 Single phase

Short circuit impedance 8.09％ 5.66％

Rated current of the high and low

sides 103.9/2309.4A 1.8/159.1A 500A 变比：5/5A

Rated voltage of the high and low

sides 20/0.9KV 20/0.22KV 220V

Temperature rise 100k 100k

2 Operation and Maintenance of Distribution Devices 2.1 General Manual for Distribution Devices

The distribution devices in this Manual include busbar, switch, knife switch, PT, CT, lightning


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arrestor, wave trapper, coupling capacitor, conducting wire, cable, distribution board etc.

The phase sequence of each circuit of distribution devices should be consistent. Indoor hard wires and outdoor busbar bridge should apply phase color paint, phase A is red, phase B is yellow and phase C is blue.

Designations and codes of equipments should be respectively marked on the distribution boards, compartment doors or equipment shells of distribution devices.

Shells of all equipments of distribution devices should be reliably earthed.

All cable inlet and outlet holes, cable through-floor and wall holes for outdoor distribution devices should be covered and sealed off; vent holes on doors of distribution devices and windows should be provided with measures preventing rain, snow and sand entry, and fences preventing beasties.

Outdoor distribution devices should be equipped with lock device and interlock device to prevent electrical error operation accidents.

In order to avoid joint oxidation resulting in contact resistance rise, the normal temperature must not exceed 70℃ at the joint of knife switch and wire, and the connection of wires and cables; the normal operation temperature of copper and aluminum wire should not also be higher than 70℃.

The rated current of transformer device must not be exceeded in the normal operation, otherwise, the operation mode should be changed or the operation load should be reduced.

There must not be open circuit in the secondary side of current transformer, and a short circuit is not permitted in the secondary side of voltage transformer.

It is permitted that a withdrawable switch trips with voltage after the electric operation failure, but it should make sure there is no fricative sound of vacuum damaged in advance.

A record should be made after the circuit breaker switches off the fault current, and the equipment should be checked in detail at the same time, if any defect of equipment is found, it should be informed to maintenance personnel to handle.

Lightning arrestors on a busbar must be out of operation before the withstand voltage test of the busbar is carried out.

Any working must be prohibited on the earthing cables of lightning arrestors, or inside the fences of arrestors in thunder storm.

2.2 Patrol Inspection of Contribution Devices

Doors and windows are closed in the distribution room, the lighting is adequate, cable holes are blocked tightly, and the fences on doors and windows are in good condition to preventing beasties entering.

The cover plates of cable trenches are complete.

The wire connecting parts and the equipment joints contact well, there is no screw looseness and overheating phenomena with wires and joints, there is no broken wire and broken strand phenomena.

Porcelain insulators and bushings are clean without damages, cracks, flashover traces and discharge phenomena.

There is no leakage with oil filled equipment, and the oil color is clear, there is no foreign matter in oil, and the oil level is normal.

There is no noise and discharge sound with circuit breaker and instrument transformer; the there is no looseness and dropout phenomenon on the instrument transformer secondary wire terminals.

The operating mechanisms of circuit breaker and isolating knife switch are in good condition without broken damage phenomenon, and there is no break and dropout phenomenon of pin.


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There is no rust and burn phenomenon on the contact heads of isolating knife switch; the contact heads contact well without overheating phenomenon.

Cable sheaths are complete; there is no oil leakage and discharge phenomenon on the contact.

Earthings of equipment shell are in good condition.

No pressure low alarm for SF6 pressure occurs; operation and startup and stop of oil pumps are normal.

All heating devices for all operating boxes in 150kV step-up station are normal, and can normally switch on and switch off according to the specified temperature, and the doors of operating boxes and terminal boxes should be closed tightly.

The indications of signal and position indicators are normal.

There is no break on generator enclosed busbars with micro positive pressure; there is no seeper in the gas tank of enclosed busbars.

2.2.1 Special check items for distribution devices:

1）It should be checked in strong wind day whether or not there is any violent swing of busbars and lead wires of all parts, whether or not the connecting parts become loose, whether or not there is any foreign matter brought by strong wind all around;

2）There should not be abnormal discharge and flashover, burn trace and rupture phenomena on all porcelain insulators and bushings in fog and rain day;

3）The sag of lead wires and tensile force of connecting wires should be checked in high air temperature, whether or not the oil level of equipment is too high or too low;

4）The distribution room should be checked in heavy rain day whether or not there is any water leakage;

5）The relevant equipments should be checked in detail when equipment takes place abnormity or fault.

2.2.2 Check after circuit breaker fault trip

1）Whether or not there is any obvious fault in the outside of the circuit breaker, for example, crack and damage on support insulators, fracture insulators and capacitor insulators etc.

2）Whether or not there is any leakage phenomenon of SF6 gas; whether or not there is any capacitor oil flowing out.

3）Whether or not signals “Three Phases Asynchronization and Non-All-Phase Operation” occur at accident opening; the relevant equipments will be considered as important objects to inspect according to the fault and the signals.

2.3 Normal Operation and Maintenance of Cable

2.3.1 The surface temperature of cable does not exceed 60℃ in normal operation.

2.3.2 The normal operation voltage of cable should not exceed 15% of its rated voltage.

2.3.3 Overload of cable is permissible at accident, but the following rules should be complied with:

1) Cable below 1kV is only permitted with 10% overload to continuously operate 2 hours;

2) 6kV cable is only permitted with 15% overload to continuously operate 2 hours;

3) The normal load immediately consumes when the overload time is over;

4) The interval of intermittent overload must be 12 hours above, and the next overload can be permitted.

2.3.4 Normal check items of cable:


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1) The cover plate of cable should be completely put on;

2) There should be no seeper or foreign matter in the cable trenches;

3) No goods can be pile on cables;

4) The cable head should be complete and clean without discharge or oil leakage, overheating, discoloration, burned taste etc.

5) Cable earthing wire should be in good condition without looseness, breakage and dropout phenomenon, the sheath is not damaged, and the cable temperature should not exceed the permissible value.

The temperatures of several cables used in parallel should be same, if there is obvious difference, tong tester should be used to measure the current distribution, if the current distribution is unbalanced, it should be reported, and the cable with the maximum current should not exceed the permissible value.

2.4 Operation Maintenance of Isolating Knife Switch and Busbar

2.4.1 The loads which are allowed to be cut off by isolating knife switch are as follows:

1) Opening and closing of voltage transformer.

2) Opening and closing of lightning arrestor without thunder and lightning.

3) Opening and closing of no-load busbar.

4) Opening and closing of neutral point earthing knife switch of transformer.

5) Opening and closing of no-load transformer with excitation current ≯2A and no-load line with capacitance current≯5A.

2.4.2 The closing of knife switch should be correct and rapid and decisive, but there must not be excessive impact at the end of closing. In case false closing or closing on fault circuit occurs, the closing operation should be fully completed and the knife switch can not be opened.

2.4.3 The opening of knife switch should be slow and cautious, it must be paid attention whether or not there is any abnormal arc to produce at the moving contact and static contact just separating during opening operation, if yes, and the knife switch must be immediately closed.

2.4.4 The isolating knife switch should be locked after operations are completed, and the operation conditions should be carefully checked, the moving contacts and the static contacts should contact well and should not deflect, or the contact surface is too small;

2.4.5 The permissible temperatures of knife switch and busbar are 70℃, there should not be overheating phenomenon in operation.

2.4.6 Check and requirements after knife switch and busbar overhaul:

1) Withstand voltage tests are qualified (or insulation resistances are qualified);

2) All joints are complete and clean, the closing positions are appropriate, contacts are good, and operations are flexible;

3) All screws of joints are tightened and in good condition.

4)Driving rods are in good condition, pins do not drop out, auxiliary contacts are in good condition, and positions are correct.

5) All insulations are clean without crack and scratch;

6) There is no object and foreign matter to obstruct operation all around;

7) Markings such as designation and code of equipment should be correct and clear.

2.4.7 Check of knife and busbar in operation:

1) Insulators are clear without crack and discharge phenomenon;


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2) All contacting parts are tight without looseness and overheating phenomenon, without abnormal noise and metal fitting vibration phenomenon;

3) Driving bars and pins are in good condition, and position indications are correct.

2.5 Operation and Maintenance of Instrument Transformer

2.5.1 A short circuit can not occur in the secondary circuits of voltage transformer during operation, and load can not be carried without control; a open circuit can not be occur in the secondary circuits of current transformer;

2.5.2 Checks and requirements after overhaul of voltage and current transformers

1) They are qualified by testing;

2) Eathing points should be connected well, there is no foreign matter to obstruct operation, all parts are clean without oil leakage, and oil level and color are normal;

3) Screws of all parts are tight without looseness; there is no abnormal phenomenon on bushing such as crack;

4) HV fuses of voltage transformer are complete and contact well;

5) Secondary wirings of current transformer are in good condition, open circuit must not occur;

6) Phase positions of secondary circuits are correct.

2.5.3 Check items of voltage and current transformer in normal operation:

1) Oil level and oil color are normal without oil leakage;

2) Bushings are clean without crack and discharge phenomenon;

3) There is no overheating phenomenon for all joints, earthing wire should be complete and in good condition, screws of all parts are tight without discharge phenomenon.

4) There is no abnormal noise or transformer electromagnetic sound in current transformer;

2.6 Operation and Maintenance of Lightning Arrestor

The insulation resistance can not be measured when a lightning arrestor is to come back operation, but it can be put into operation only after it is tested and compared with leak current up to standard by the test personnel.

All arresters are put into operation in all year.

Bushings are clean without crack and spark discharge phenomenon.

There is no looseness and discharge phenomenon with connecting wires.

Earthing wires are firm without looseness.

Arresters should be carefully checked after thunderstorm whether or not there is any flashover trace on the outer bushings, there is any discharge sound in the inside of arrestors, whether or not the discharge recorder has acted.

2.7 Operation and Maintenance of Enclosed Busbar

A leakage test of enclosed busbar should be carried out and qualified after overhaul, the actual air leakage and ideal air leakage ratio should not exceed 4% per hour, if unqualified, the soapy water will be used for looking for leakage point (handled by maintenance personnel).

Check the air supply device is in good condition, the control power supply is put into operation. The air supply temperature should not be lower than 20℃.

The air source valve of the air supply device is opened to supply air to the enclosed busbar; this dry air is used for evicting humid air in the enclosed busbar.

The dry air can be cut off after it circulates in enclosed busbar for 15 to 24 hours, and the water drain cap and plug should be resumed. (The dry air must circulate 24 hours in enclosed busbar


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after overhaul, other will depend on circumstances)

The air source of enclosed busbars should keep 0.7MPa pressure after the generator parallels on.

Enclosed busbars should usually operate to keep in micro positive pressure (300 to 2500Pa), and the pressure is automatically regulated.

1) Air supply will be automatically carried out when it is lower than 300Pa.

2) Air supply will be automatically stopped when it reaches 1500Pa.

3) The safety valve will act (discharge air) when it reaches 3500Pa.

4) The rated air injection amount of automatic device is 25.2m３/h.

5) If automatic control is in malfunction, the pressure in the enclosed busbars should be manually controlled in 300Pa to 2500Pa, and the maintenance personnel will be informed for handling.

2.8 Operation and Maintenance of Trolley Type Switchgear

2.8.1 Patrol Inspection

Smoking is prohibited inside rooms; a hot work must handle a hot work permit.

Lock management are applied to distribution rooms where any person must not freely pass in and out. Non operator who needs entering this area to work must handle a work permit, and will be guided to enter into this area by the supervisor.

Electrical or I&C personnel must be specified to supervise installation and maintenance workings carried out in the distribution rooms. The supervisor must strictly carry out supervision on site and must not freely leave after handling work permit.

Check that lightings are adequate in distribution rooms, if lamps are damaged, the maintenance personnel should be immediately informed to replace.

Check whether air conditionings are normally operating, the room temperature must not be higher than 35℃. If higher than this temperature, the room temperature must be decreased by all possible means.

Check whether there is any water leakage in room, and it must ensure there is enough dryness inside distribution rooms.

There must not be ash deposit and dust deposit on the protection panels and the ground must be kept clean in distribution rooms.

Check that fans of panels and cabinets runs well, all cabinet and panel doors are closed to avoid dust entering into the panels and cabinets.

Check that the fire fighting facilities and equipments are adequately prepared and in good standby state.

It must be checked that each door is locked to prevent other persons entering when leaving distribution rooms.

When the work permit is finished, the working personnel must go to the site for inspecting, and “Materials and field must be cleaned up after a working is completed”, each door of room must be lock in time.

Patrol inspection items of trolley type switchgear

1) Operators must not make bold to open the back cover board of switchgear.

2) The back cover board must be closed well, the sight glass must be clear, lighting is adequate, and bulbs are in good condition.

3) Contact heads contact well without overheating phenomenon.

4) Micro computer protection control device is normally put into operation, and the values


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displayed are correct, protections are put into operation as specified.

5) The break phase indicator lights of the red, yellow, and blue three-phase fuse are normally on.

6) The opening and closing state indicator lights are on and conform to the equipment operation state.

7) Check that the energy storage indicator light is in good condition and the energy storage switch is put into operation as required.

8) It is to be checked the selector switch of control mode has been correctly put into operation as required.

9) The protection straps have been put into operation as specified.

10) Active curtain board has closed in correct position.

2.9 Operation Manual for Auxiliary Power 6KV System Vacuum Switch and Vacuum Contactor (F-C Circuit Switch)

2.9.1 Vacuum switch trolley and F-C circuit switch trolley meets the following interlocks

An interlock, which is located in the trolley chassis to prevent trolley moving, can be unlocked and the trolley can depart from the work position or open position/test position only when the circuit breaker on the trolley is in open state.

The electrical control circuits on the trolley can switch on only when the trolley is locked on the open position/test position or work position, at the same time, the interlock located in the trolley chassis to prevent circuit breaker closing can be unlocked, the circuit breaker can be closed.

The electrical closing circuit and closing mechanical driving system of circuit breaker are locked and the circuit breaker can not be closed when the trolley is placed in the middle (move) position.

An interlock preventing the closing of switchgear earthing switch by trolley can be unlocked only when the trolley is in open position /test position or drawout position, here the earthing switch of switchgear can be closed.

The interlock structure on the operating shaft of earthing switch will obstruct the trolley moving when the earthing switch is in closed state, so that the trolley can not be put into the work position.

The secondary plug can be inserted in and pull out only when the trolley is in open position/test position.

The secondary plug can not be pulled out after the trolley apart from the open position/test position, during putting into the work position and after reaching the work position.

The lower door of switchgear or the back blanking plate of cable chamber can be opened only when the earthing switch is in closed state. The earthing switch can be opened only when the back blanking plate of cable chamber is closed in.

After the F-C circuit switch shuts off primary short circuit current, an external inspection of the switch should be carried out, Check whether the fuses are blown, same size and type of fuses should be replaced after the fuses are blown, other type must not be used.

2.9.2 Auxiliary Power 6kV Switchgear

A switch newly installed or after overhaul must carry out one time of open-close test in the test position before it is put into operation. The switch with abnormal operating mechanism is prohibited to put into operation.

Under normal condition, the switch of 6kV power load is strictly prohibited to carry out open-close operation in the local switch room (including open-close test). Switches are permitted to manually trip under the following condition:


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1﹚ The switch fails to electric trip.

2﹚ A serious personal and equipment accident occurs.

6kV withdrawable switch is normally not permitted to interchange. In case a withdrawable switch fault occurs and it is necessary to supply power to the equipment, a same type and same capacity of standby withdrawable switch can be replaced after the maintenance personnel confirm the standby withdrawable switch is in good condition and it can match with the switchgear, but the switch equipment nameplate must be replaced, and the defect of fault switch should be eliminated in time.

The insulation (between sheath and wire, between wire and wire) resistance value of LV circuit of switch should not less than 1MΩ/kV relative to the rated voltage.

The permissible ambient temperature of switchgear is -15℃ to +40℃, the maximum daily average temperature: +35℃.

The indoor air should be clean, the relative humidity should not exceed 90% at temperature +25℃, the dew generated every once in a while due to temperature change should be paid attention to mitigate. 6kV switchgear is provided with temperature and humidity controllers which should be put into operation in normal condition.

Positions and functions of 6kV withdrawable switch

1﹚ Work position: The primary circuit and secondary circuit of switch are switched on, and the switch is in working state

2﹚ Test position: The primary circuit of switch is apart from the system, it can carry out operating function test.

3﹚ Repair position: The primary circuit and the secondary circuit of switch are switched off, and in isolated and power cut state

Before a switch is placed in test position and repair position, it should be checked that the switch is in open position, the mechanical trip device of the switch body acts flexibly and there is no blockage phenomenon when it is drawn out.

Before withdrawable switch is put into the test position and the work position, it should be checked the earthing knife switch is in open position, there is no blockage phenomenon when putting in, and there is no foreign matter on the switch body.

The back door of switchgear is strictly prohibited to open for carrying out work when the withdrawable switch is in work position.

Before the earthing knife switch is operated, it should be checked the switch has been drawn out to the repair position or test position, and the back door of switchgear is in closed position.

2.10 Manual for Check and Operation of GIS Combined Electrical Equipment

2.10.1 Normal patrol inspection items of GIS combined electrical equipment: whether or not the position indication of switch, knife switch, earthing knife switch conform to the actual conditions. Whether or not all signal indications of local control cabinet on site and the position of control switch are correct, and whether or not the signal relay has acts. Whether or not indications of various pressure gauges are normal; whether or not there is any leakage of SF6 gas and hydraulic system; whether or not there is any damage and rust for all kinds of pipes and valves in which the opening and closing position are correct. Whether or not the indication value of action counter of lightning arrester takes place change. Whether or not there is any overheating on the external incoming line terminals, and whether or not there is any crack and damage on the insulators. Whether or not there is any abnormal noise or peculiar smell. Whether or nor there is any rust and damage on shells and supports; whether or not the earthing is in good condition; whether or not all kinds of box doors are closed tightly. Whether or not the ventilation system is in good


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condition.

2.10.2 Manual for GIS Combined Electrical Equipment in Normal Operation

In addition to comply with the general safety work rules, it should pay attention to the characteristics of SF6 gas in operation of GIS device: first, SF6 gas and its electric arc decomposed matter can leak to pollute environment and endanger personal safety; secondly, the contact potential harmfulness can be caused in equipment internal fault or operation

In order to prevent SF6 gas deposited in low-lying place to result in anoxic asphyxiation accident, operators should open ventilating fans for 15 minutes before they patrols equipments and the maintenance personnel enters into the working site.

Operators should record the SF6 gas pressure and ambient temperature of each gas chamber of GIS combined electrical equipment in each patrol inspection. If they find any abnormal leakage phenomena such as gauge pressure drop, pungent smell, feeling unwell in the patrol inspection, they should handle as per the safety protection Manual of SF6 chamber leakage.

The pressure parameter of each gas chamber of GIS combined electrical equipment in operation should conform to the requirement specified.

2.10.3 Operating Manual of GIS Combined Electrical Equipment

In normal operation of GIS combined electrical equipment, the switch and electric knife switch must use remote operating mode, and it must be checked whether or not the position signal of equipment is correct after operating. The operation on the local control cabinet can only be used in equipment maintenance or special condition. When the GIS combined electrical equipment is operated, anybody must stop the work on the equipment shell and apart from the equipment till the operation is over. Operators should wear insulation gloves and keep a specified distance from the equipment when the earthing knife switch is manually operated.

There are electrical locking devices for operating circuit of each switch and knife switch of GIS combined electrical equipment, if obstructions occur in operation, it is considered whether or not the locking device is normal. See anti-misoperation device section for specific lock logic.

In order to avoid error closing operation of earthing knife switch in 150kV line with power on, it should be checked in site that the line voltage transformer has truly been in power failure and there is no indication on leaking current meter of line arrester after the switch and the isolating knife switch are opened by remote control, and then it is verified by dispatchers, afterwards, the closing operation of line earthing knife switch can be carried out.

2.10.4 Accident and Abnormal Operation of GIS Combined Electrical Equipment

If any abnormal condition is found in patrol inspection such as gauge voltage drop, abnormal sound, pungent smell etc, it should be reported to the dispatcher and the working section management, the causes must be found out and relevant measures must be taken.

When SF6 pressure drop alarm occurs, the pressure on pressure gauge and gas chamber should be immediately checked on site to make sure whether or not there is leakage, if a mass of leakage are found, it should be reported to the dispatcher to apply for power cut to handle.

When SF6 pressure of switch drops to below the lock value and the switch is in open-close lock state, the switch should be immediately changed to non-auto mode and it should be reported to the dispatcher and the working section management, and waiting for instructions to handle.

When GSI device accident results in gas leakage, personnel will not be permitted to freely enter into the site, at first, all ventilating devices should be switched on for ventilation, gloves and gas mask must be worn and protection clothing must be put on for entering into the site.

2.10.5 Acceptance Items after Overhaul and Installation Test of GIS Combined Electrical Equipment

GIS combined electrical equipment normally only carry out minor repair and does not carry out overhaul. A minor repair will be considered only when it operates over a long period of time (10


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years above) or the times of trip operations resulting from accident, serious abnormal and fault exceed the times specified. The normal minor repair period is once per biennium. In addition to execute the contents of electrical and mechanical characteristics as well as preventive test for the relevant equipments, the following contents will be carried out in the minor repair:

a) The water content of SF6 gas should conform to the Manual in the slug test.

b) The leakage test standard is “leakage rate per year”<1%.

2.10.6 Acceptance items of GIS combined electrical equipment:

a) Installation should be fixed and firm, appearance is clean and complete, and the acting performance conforms to the Manual.

b) Leakage rate and water content of SF6 gas should conform to the Manual.

c) The interlock device of combined electrical equipment and its drive mechanism should be normal without blockage phenomenon, the open and close indications are correct, and the secondary contacts and electrical locking device should correctly and reliably act.

d) Alarm and locking setting values of density relay equipped should conform to the Manual, and signals act correctly.

e) The incoming line power-on display device should be able to reliably lock the quick earthing knife switch of incoming line.

f) Paint is complete, phase color markings are correct, and the earthing is in good condition.

g) Open - close test (including remote operation) is qualified.

h) Electrical test report is qualified, records are complete and there is conclusion for being able to put into operation.

3 Abnormal Operation and Accident Handling for Switchgear 3.1 General Principle of Accident Handling

Prevent an emergency from evolving into an accident, eliminate the causes and relieve threat against personnel and equipments.

Take all possible actions to ensure normal operation of the auxiliary power supply systems.

Take all necessary actions to ensure that other equipments sustain normal operation, adjust the unit output if necessary to guarantee power supply to users, provided that the provisions on generator overload protection are observed.

Restore power supply to users as soon as possible.

Adjust the operation modes to restore normal operation.

During accident handling, operators must be present at their posts and rapidly execute orders issued by shift supervisors to accomplish the above tasks. Operators are allowed to leave their posts and stop equipment operation only when the shift supervisors issue an order to do so or persons and equipments are in danger

3.2 Accident Handling Procedures

Determine the nature and scope of emergency situations based on instrument indication, actions of protections and automatic devices, tripped circuit-breakers and visual examination.

It is necessary to take all necessary measures to relieve any threat against persons and equipments, and stop equipments if necessary. If the equipments don’t constitute a threat against persons and equipments, immediately restore normal operation. Isolate normal equipments from failure equipments, and start up standby equipments if necessary.

Perform inspection and tests immediately to investigate equipment damage and impact upon power plant operation, inform the management and maintenance personnel on a timely basis, and


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take safety precaution for repairing failure equipments.

During accident handling, operators must report the situations and each response stage to shift supervisors rapidly, accurately and briefly. The following information need be reported:

1) Circuit-breakers tripped conditions;

2) Action of protections and automatic devices;

3) Change in system frequency, voltage and load;

4) Equipment damage;

5) Other phenomena associated with emergency situations.

3.3 In case of any of the following emergency situations, operators may firstly deal with it and then report to the shift supervisors:

Power failure which will cause direct threat against life;

Isolate damaged equipments.

Cut off power supply to equipments which may be damaged;

In case of busbar voltage loss, open the circuit-breakers of synchronization lines connected to the busbar if power recovery is possible.

In case of total or partial loss of auxiliary power, restore auxiliary power supply.

3.4 Manual on Accident Handling

In case of emergencies, only persons, plant leaders, department leaders and engineers participating in accident handling are allowed to be present at the control room and other persons should leave the site.

In case of emergency situations involving the power system, operators should rapidly execute all orders issued by dispatchers and report the execution to dispatchers.

In case emergency situations only involve the power plant, operators should rapidly and correctly execute the orders issued by shift supervisors and foreman and report the execution to them on a timely basis.

If it is expected that an order will endanger the safety of persons and equipments, operators should refuse to execute such order, report the reasons to the relevant leaders and keep records.

In case of communication failure, the priority should be given to the safety of power plant equipments. System demand for power supply should be satisfied if possible, in accordance with the Manual on system voltage and frequency as well as dispatching Manual.

During accident handling, the system of attendance and read-back should be strictly abided by. Don’t take hasty action.

Emergencies which occur during shift handover should be dealt with by handing-over operators. In this case, taking-over operators shall coordinate with handing-over operators. Relief of a shift can be carried out only after accident handling has been basically completed.

A person shall be assigned to keep various records, including operation of relaying protection and automatic devices, phenomena, various indications, sequence and execution time for various orders and load recovery time. The relevant signals can not be restored until making records.

After accident handling is completed, the shift supervisors and foreman shall keep records of accident handling to analyze the causes.

3.5 Accident handling to abnormal system frequency

The system frequency should be 50HZ±0.2HZ.

When the frequency is smaller than 49.8Hz, operators should immediately increase the active power output to the maximum value so that the system frequency is greater than 49.8Hz (without


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waiting for dispatching orders). If the system frequency is still lower than 49.8Hz after the units has operated at the rated power output, operators should report to dispatchers.

When the system frequency sharply decreases due to power grid failure, the low frequency protection of the units will be triggered and the circuit-breakers at the outgoing end of generator-transformer unit will be tripped. In this case, auxiliary power supply systems will be changed over to sustain normal operation of turbines, generators and boilers. Operators should immediately contact dispatchers and prepare for synchronization with power girds.

When the frequency is higher than 50.2 Hz, operators should report to the shift supervisors and adjust the load according to the actual situation of the power plant. If the load adjustment deviates from the daily load curve, contact dispatchers on a timely basis.

3.6 Accident Handling to Abnormal System Voltage

The allowable variation of 150kV system voltage is specified by the provincial dispatch center. The busbar voltage should be maintained in the range of the variation specified by the dispatching center.

When the busbar voltage is higher than the specified value, adjust generator excitation (generator under-excitation operation and under-excitation degree shall be determined according to the result of under-excitation operation tests) so that the busbar voltage is again within the normal range. Adjustment made on generator excitation should ensure that the auxiliary 6kV and 380V system voltage are normal and the temperature at generator parts is normal.

When the busbar voltage is lower the specified value, increase the generator inactive power output. If the system voltage is excessively low, it is possible to apply for decrease in active power output so that the inactive power output of the generator can be increased. However, the generator stator current should not exceed 105% the rated value.

If a low busbar voltage endangers normal operation of the auxiliary equipments, operators may change over auxiliary power to 30 startup/ standby transformer to adjust auxiliary power voltage. If it is impossible to maintain the auxiliary power voltage, report to the shift supervisors.

3.7 Power system oscillation

(1). Phenomenon

1）The generators, transformers and lines experience sharp and periodic oscillation;

2）The generators and transformers issue abnormal and rhythmic roars which are synchronous with the oscillation of the above-mentioned parameters;

3）The conveyed power of interconnection tie between two power grids which are out of synchronization experience oscillation.

4）A significant frequency difference between two systems (power plants) which are out of synchronization exists. The frequency rises at the supplying end and drops at the receiving. In addition, the frequency slightly varies.

5）The generator and busbar voltage swing periodically. In general, the voltage will drop. The maximum voltage fluctuation appears at the oscillation center and the voltage drop to zero periodically. In the areas far away from the oscillation center, the voltage fluctuation also occurs and lamps twinkle alternatively. In general, the forced exciters of the power generating units close to the oscillation center will be triggered.

(2). Solution

1）In case of system oscillation, whether frequency rise or drop, the operators of concerned power plants should disable the AGC device, increase inactive power output of generators, make use of their overload capability and raise system voltage even if dispatchers don’t issue an order to do so. The maximum allowable generator voltage is 22kV and the voltage of 150kV


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busbar should not exceed 165kV.

2）Operators of power plants which frequency drops should immediately increase the active power output to the maximum value and make full use of the reserve capacity and overload capacity of the units to raise the frequency without waiting for dispatching orders.

3） Operators of power plants which frequency rises shall immediately decrease the frequency by decreasing the active power output until the oscillation disappears. However, the frequency should not be lower than 49.5Hz and normal power supply from the auxiliary power supply system should be guaranteed.

4）If the oscillation results from connection with asynchronous units, operators should immediately disconnect the unit from power grids.

5 ） When generator under-excitation operation or a high power factor results in out-of-synchronism, operators should immediately reduce active power output and increase excitation current so that the unit resumes synchronous operation without waiting for dispatching orders. If such attempt failed, disconnect the units from the systems, inspect the units and allow the units to be connected with the systems as soon as possible.

6）If loss-of-excitation occurs in an operating unit, but loss-of-excitation protection is not triggered or loss-of-excitation results in system oscillation, power plant operators should immediately disconnect the units from power grids even without dispatching orders.

7）In case of system oscillation, the plant operators should not disconnect the units from power grids unless otherwise specified in accident handling Manual. When the frequency is low enough to impair normal operation of the auxiliary power supply system, the plant operators should disconnect the auxiliary power supply system and some load from the systems according to the established auxiliary power supply assurance measures. It is prohibited to disconnect the units by opening the generator terminal circuit-breakers. When system oscillation disappears and the frequency is normal again, the plant operators should allow the unit to be connected with the power grids.

3.8 Busbar failure

After busbar voltage loss occurs, the operators should immediately report to dispatchers, open all circuit-breakers on the busbar and rapidly restore the affected auxiliary power supply.

If voltage loss results from malfunction of one of the two busbar protections, turn off the failure protection and then restore busbar operation.

If two sets of protections are triggered and the system undergoes a surge during emergencies, it is necessary to investigate the cause and eliminate failures. The operators should raise voltage from zero with the approval of the plant leaders. If all is right, apply for resuming busbar operation to dispatchers.

If busbar voltage loss results from circuit-breaker failure protections, open the blade switches on the both sides of the failure circuit-breakers, disable the failure protection and then supply full voltage to the busbar.

Before power supply recovery, it is necessary to thoroughly check busbar and equipments connected with it no matter which reason causes busbar voltage loss.

3.9 Line tripped

a) Phenomenon

An audible alarm is activated.

The green lamp is flashing and the indication on meters is zero.

The associated protective functions of the microprocessor-based protections for tripped line are triggered and reclosing may occur.


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The disturbance recorders are triggered.

b) Solution

Report to shift supervisors, check protection and reclosing action and circuit-breaker body.

If the reclosing action fails, it is not allowed to manually close circuit-breakers again.

Manually close the circuit-breaker once if SINGLE-SHOT reclosing is set and reclosing fails after single-phase tripping. In this case, it is unnecessary to check synchronization. In case of three-phase tripping, the operators should wait for the orders.

Immediately check whether the line is live if TRIPLE-SHOT reclosing is set and circuit-breaker fails to reclose. If the line is live, manually close the circuit-breakers after obtaining approval of shift supervisors. In this case, it is necessary to check synchronization. If the line is dead, the operators should deal with the emergencies following the orders.

Immediately close the circuit-breaker once if GENERRAL-SHOT reclosing is set and circuit-breakers fails to recluse after single-phase tripping. Don't manually close the circuit-breakers again if such attempt fails. If it is a three-phase tripping and circuit-breakers fail to recluse, check whether the line is live or not. If YES, immediately connect the units with power grids. If NOT, the operators should wait for orders.

Thoroughly check circuit-breakers on the failure line.

Reset and record the signals

The following should be recorded:

1) Time when the circuit-breakers are tripped;

2) Action of the protection and automatic devices (including indications on alarm window and devices etc)

3) Change in meter indication at the time of tripping;

4) Other information about accident handling

3.10 SF6 Circuit-breaker refusal to trip

a) Phenomenon

After a trip switch is operated, the red lamp is flashing and the indication on ammeters does not change.

b) Possible causes

The operating voltage is too low and the SF6 pressure is lower than the block value.

Abnormal changeover of operating handle contacts, abnormal changeover of carriage circuit breaker's auxiliary contacts, loose connection of auxiliary contacts.

Operating power cables are loose or fuses are blown.

Tripping coils are burnt or broken.

c) Solution

Reset.

If the operating voltage is excessively low, immediately adjust it to the normal value. In case of emergencies, withdrawable switch may be manually tripped.

In case of the failure of operating power source, check and repair operating power source.

If the tripping coils or iron cores are failure, inform the maintenance personnel.

3.11 Lower Gas Pressure in SF6 Circuit-breakers

When the pressure drops to the alarm value due to SF6 leakage, a “Low SF6 Pressure” alarm will be generated, but the opening circuit and closing circuits will not be blocked. In this case, inform


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the relevant personnel to make up SF6 gas and keep the record of gas makeup.

When the pressure continues to drop to the block value, the closing circuits and opening circuits will be blocked and an “Operation Prohibited due to Low SF6 Pressure” signal will be issued. In this case, the circuit-breakers can not perform opening or closing operation. If impossible to recover a normal gas pressure, report such situation to shift supervisors and allow the circuit-breakers to be out of service after obtaining the approval of dispatchers.

In case of significant SF6 leakage, take appropriate measures to protect maintenance personnel against toxic gas. Otherwise, anyone is at least 5 m away from the leaked circuit-breakers and stay upwind.

3.12 SF6 Circuit-breaker Failure to Close

a) Phenomenon

After operating closing switches or buttons, the alarm horn sounds, the green lamps of the circuit-breakers is flashing and no indication is given by the meters.

b) Possible causes

The circuit-breaker is not ready for synchronous closing, or the synchronizer is not put into operation as required, or thermal conditions required for closing of auxiliary closing circuits are not met.

No energy is stored in the circuit-breakers, SF6 pressure is lower than the block value or other closing conditions are not met.

The operating power is unavailable, operating circuits or closing contactors have broken wire.

The closing power fuse is loose or blown or the closing coil is burnt or broken.

Changeover of circuit-breaker's auxiliary contacts is failure, the plugs of withdrawable switches are not properly inserted or loose connection of withdrawable switch's position contacts exists.

The operating mechanisms are damaged or pins are missed.

After the circuit-breakers are tripped, the protection is not reset and therefore the tripped signal still exists.

c) Solution

Operation and audible alarm reset.

Check whether the synchronizer is correctly put into operation and the synchronization conditions are met;

If the operating voltage is excessively low, adjust the DC system voltage.

Check whether the operating and power fuses are in good order or blown. If the circuit is OK, replace the fuses with a new one and then close the circuit-breaker.

Check whether the auxiliary contacts and position contacts of the circuit-breakers can perform changeover properly and the plugs of withdrawable switches are normally plugged.

Check the operating and closing circuits for loose terminal connection, damaged coil or broken wire, etc.

If the closing coil can be normally energized, the mechanical parts may be failure. In this case, inform the maintenance personnel.

3.13 On-load closing isolators or closing isolators with earthing conductor

After an isolator is incorrectly closed, it is not allowed to immediately open it in any case. It is necessary to firstly open the circuits using a circuit-breaker before opening the isolator.

3.14 ON-load opening isolators

If the isolator has been opened, it is prohibited to immediately close it. It is allowed to re-close


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the isolator only after the circuit-breakers are opened.

Immediately re-close the isolator if operators find isolators to be incorrectly opened when the moving contacts don’t separate from fixed contacts or separate slightly from fixed contacts, and the isolator is slowly opened,

3.15 Blown PT fuse

a) Phenomenon

The indication on voltmeters is abnormal, indicating that voltage circuits may have broken-wire signal. An earthing signal may appear if the fuse on the HV side of the PT connected in y0/y―Δ manner is blown.

b) Response

Accurately record the exact time when the fuse was blown. Disable the relevant protection and automatic devices with the approval of shift supervisors. Inform the relevant departments (avoid misjudgment resulting from meter failures), investigate the cause and replace the fuse. If the new fuse is also blown, don’t continue to replace the fuse, but investigate the extract cause and report to leaders.

3.16 Open circuit of CT’s secondary side

a) Phenomenon

The ammeters and wattmeter provide abnormal indication, the protective CTs may signal that there is a broken wire in current circuit, and the CTs may issue hum or smoke appear.

b) Response

Disable the relevant protection and automatic devices with the approval of shift supervisors. Inform the relevant departments (to avoid misjudgment due to meter failure), take appropriate safety measures and attend short-circuited secondary side. If impossible to correct the problems, stop the CTs on a timely basis.

3.17 Immediately disable PTs and CTs in case of any of the following conditions.

The fuses on PT’s HV side are continuously blown;

Extremely overheated, sign of oil or smoke and burnt odour;

Crackling sound or other noises are issued from inside PTs or CTs.

Spark discharge exists between leads and enclosures.

The PT or CT enclosures are broken and seriously leaky.

3.18 Lightning arrester failure

If the protections fail to operate in case of explosion or breakage of lightning arrester housing or discharging into ground, open all power circuit-breakers connected to the lightning arrester systems with the approval of shift supervisors. Restore the operation of lightning arresters after eliminating such failures.

In case of any of the following conditions, open the power circuit-breakers and treat the lightning arresters

1) There are cracks on arrester bushings;

2) The connecting wire or earthing conductors are loose or not connected.

3) Electric discharge occurs on porcelain insulators or bushing

4 Accident handling to auxiliary power supply system failure 4.1 General principle of accident handling

If HV auxiliary transformers are tripped, check whether the standby power supply of 6kV busbar


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is interlocked. If NOT, it is allowed to manually force supplying power once. If certain branch circuit-breakers are tripped due to overcurrent protection of LV branches of HV auxiliary transformers, it is prohibited to force supplying power to this branch busbar no matter whether standby power supply is interlocked or not. It is allowed to supply power to the busbar only when failures have been eliminated (isolated) and the result of insulation resistance is acceptable.

6kV busbar voltage loss: if standby power circuit-breakers are tripped again after the operation of rapid changeover devices or manual forced closing circuit-breakers, never force supplying power to the busbar again in any case. Investigate the causes, eliminate (or isolate) failure points, measure the insulation resistance and finally restore power supply to the busbar.

380V busbar voltage loss: If the cause is a failure of LV auxiliary transformers, it is allowed to supply power to 380V busbar using bus-tie circuit-breakers after the transformers are suitably isolated. If you are uncertain that the busbar has failed, don't supply power to the busbar using bus-tie circuit-breakers to prevent failures from becoming more serious.

4.2 Total loss of auxiliary power

a) Phenomenon

The noises suddenly change inside the computer rooms and all rotating machines are tripped.

Normal lighting is totally lost and emergency lighting systems are put into operation

The generators, turbines and boilers are tripped;

b) Response

Immediately start diesel-engine generators and recover power supply to the protective section.

Pay close attention to DC system busbar voltage, battery discharge and UPS system operation;

Pay close attention to generator sealing oil pressure, and reduce hydrogen pressure if necessary to prevent hydrogen leakage;

Investigate and isolate the failure points as soon as possible.

Contact dispatchers to restore the operation of the startup/ standby transformers if the transformers and their channels are normal.

Report to dispatchers, restore the operation of 150kV systems via the tie line as soon as possible, and firstly restore the operation of the single busbar if necessary.

Restore the operation of 6kV and 380V busbar sections which don't failure, as soon as possible;

Immediately start the unit once it is ready for startup, and allow the tripped units to be connected with the systems as soon as possible.

Keep and submit the relevant records to leaders.

4.3 6kV busbar failure

a) Phenomenon

An audile alarm is activated and the system undergoes a surge.

The operating power circuit-breaker in failure section is tripped and a green lamp is flashing.

The standby operating power circuit-breaker in failure section is closed and then tripped and a green lamp is flashing.

The voltage of the failure section is zero and the relevant protection is triggered.

b) Response

Reset audible alarms

Make the rapid auxiliary power changeover device out of service;

Investigate the operation of the protections.


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Restore power supply to 380V busbar which power failure results from 6kV busbar failure;

If the busbar section is obviously failure, release it from the system and inform the maintenance personnel. Restore power supply to the busbar after it has been repaired and the result of insulation measurement is OK.

If no significant busbar failure is found, open all isolators of the section and measure the insulation resistance of busbar. If the result of the measurement is OK, energize the busbar. Measure the insulation resistance for each load branch. Supply power to such load branch if the insulation resistance complies with the requirements. If NOT, inform maintenance personnel.

After 6kV busbar becomes normal, change over 380V auxiliary power supply system to normal mode.

4.4 Damage of 6kV withdrawable switch

Immediately cut off the DC operating power of the circuit-breaker to prevent it from tripped.

Report to shift supervisors to reduce turbine and boiler load, change over to standby equipments of another busbar, de-energize 6kV busbar at which the failure circuit-breaker is located, rapidly remove the failure circuit-breaker and restore the original operating mode.

Inform maintenance personnel so that the failure circuit-breakers are repaired or replaced.

4.5 Tripping of Miniature Switches on 6lV PT Secondary Side

a) Phenomenon

An audile alarm is activated and the signal “6kV PT Failure or Low Voltage” is sent.

The signal “MFC Rapid Changeover Device Blocked” is issued.

b) Response

Disable the rapid MFC changeover device of the busbar section;

Deactivate the low-voltage protection;

Check the PT locally;

Close the miniature switches on PT secondary side;

After the alarm condition disappears, enable the low-voltage protection

Put the rapid MFC changeover device of the busbar section into service;

4.6 Automatic circuit-breaker tripping

a) Phenomenon

The alarm horn sounds;

The green lamp on circuit-breakers tripped is flashing;

The indication on ammeters is zero;

An alarm signal is issued

b) Solution

Start up the standby circuit-breaker to ensure the unit operation;

Check for correct protection operation. If the protection is triggered due to circuit-breaker failures, deal with the failures according to the relevant Manual.

If the protection malfunctions, inform the testing personnel. After the circuit-breaker are adjusted, repaired or replaced, allow it to be put into service.

If it is a circuit-breaker failure, inform maintenance personnel to deal with it and perform tripping and closing tests. If all is in order, the circuit-breaker should be put into service.

If the problem is due to incorrect operation by local operators, the circuit-breaker may be


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immediately put into service without the need for inspection.

4.7 Circuit-breaker Refusal to Close

a) Phenomenon

The horn sounds;

The green lamp on the circuit-breaker is flashing;

b) Solution

Isolate the failure by pulling circuit-breaker to TEST position and performing operation test.

Check whether the closing conditions exist and the circuit-breakers are correctly operated;

Check for the circuit-breaker operating power and correct power voltage;

Check for intimate contact between secondary inserts and broken wire in secondary circuits;

Check for normal spring energy storage and free movement of closing mechanisms;

If operators are not able to investigate the cause of trouble or to correct the problem, inform maintenance personnel

4.8 Circuit-breaker Refusal to Open

a) Phenomenon

There is not significant change in the reading on the meters (ammeters and voltmeters)

The red lamps on the circuit-breaker are steady on.

b) Solution

Check for correct operation;

Check for the availability of operating power source and broken wire in secondary circuits;

Check the contacts of the switch used to operate circuit-breakers;

Check whether the operating mechanism is jammed or not;

If remote operation fails, manually operate electrical opening buttons or mechanical opening buttons locally after obtaining the approval from shift supervisors.

If both remote and local electrical operation fails, it is strictly prohibited to open the circuit-breaker by pulling the carriage by hand. In this case, report the trouble to shift supervisors. Open the upstream power circuit-breakers in case of emergencies. Perform such operation after transferring the load on the busbar section if possible.

Cut off power supply to the failure circuit-breakers and inform maintenance personnel for inspection and repair.

4.9 Circuit-breaker Failure to Close

a) Phenomenon

The horn sounds;

A momentary current surge exists during closing circuit-breakers

The lamp turns red and then the green lamp is flashing

b) Solution

Check for the operation of the protective devices. If failure conditions exist, check and correct the failures depending on the failure equipments.

In case of incorrect operation of the protection, inform testing personnel.

Check the closing mechanism by withdrawing the circuit-breaker to the TEST position and performing operation tests. If the operators are not able to eliminate the trouble, inform


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maintenance personnel.

4.10 380V busbar failure

a) Phenomenon

An audile alarm is active and the system undergoes a surge.

The operating power circuit-breaker in failure section is tripped and a green lamp on the circuit-breakers is flashing.

The voltage of the failure section is zero and the relevant protection is triggered.

b) Solution

Reset the audible alarms

Investigate the operation of the busbar protections.

Immediately go to busbar rooms and check for any visual failure.

If impossible to isolate or eliminate the failure quickly, allow other busbar sections to take over power supply to the MCC which power is previously supplied by the failure busbar section (it is necessary to firstly cut off the original power supply and then connect with the standby power supply).

After a failure is located, release the busbar from standby state and inform maintenance personnel.

If no significant failure is found, open all isolators of the section and measure the insulation resistance of busbar. If the result of the measurement is OK, energize the busbar using service circuit-breakers. Measure the insulation resistance for each load branch. Supply power to such load branch if the insulation resistance complies with the requirements. If a problem is found, inform maintenance personnel.

4.11 Broken 380V Voltage Circuit

a) Phenomenon

An audile alarm is active and the signal “380V Voltage Circuit Broken” is issued.

The indication on the voltmeters mounted on the LV auxiliary power control panel is abnormal;

b) Possible causes

The primary or secondary circuits of PTs have broken wires;

The 380V auxiliary PT failure;

c) Solution

Deactivate the low-voltage protection for the section;

Check for any abnormal sign of the PTs;

Replace the fuses with a new one. If the primary fuse is blown, replace the fuse after cutting off power supply to the PTs.

Put the relevant interlock and low-voltage protection for the section into service.

4.12 Overcurrent of Certain 380V Section

a) Phenomenon

The system undergoes a surge, a buzzer sounds and an alarm is activated;

The power supply to all loads of the failure section fail and the low-voltage protection trips the relevant motors.

If the busbar is short circuited, there may be smoke, fire, explosion or burnt odour in switchgear rooms,


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b) Possible causes

The failure circuit-breaker of a user of 380V auxiliary power busbar section can not be opened;

A 380V auxiliary power busbar section is short-circuited.

c) Solution

Check the operation of the protections.

If no failure is found in the circuit, it is allowed to force energizing the busbar once.

Go to the switchgear rooms to check for busbar failures or override trip due to circuit-breaker failure to operate.

If the reason is circuit breaker failure, proceed with the following steps:

1) Manually open the circuit-breakers and blade switches not tripped and energize the busbar using service power circuit-breakers;

2) Cut off power supply to the failure circuit-breakers, inform maintenance personnel, and energize the busbar only after the failure is cleared.

4.13 Immediately de-energize the cables in case of any of the following conditions:

Cables explode, smoke or catch fire

Cables discharge electricity to ground due to insulation breakdown.

Other conditions endangering cable safety exist.

4.14 Cable Catching Fire

Inform firemen, inform all operators to turn off the relevant equipments and immediately use CO2 or dry powder extinguishers, dry sand or soil to extinguish fire. It is prohibited to use foam extinguisher before cutting off power supply.

Wear gas-masks when extinguishing fire in cable trench or confined spaces.

When cables catch fire, it is prohibited to touch metallic sheath of cables by hand or move cables having metallic sheath by hand.

In order to protect against personal injury due to earthed HV cables catching fire, everyone should be at least 4m away from indoor cables and at least 8m away from the outdoor cable before de-energizing cable. Wear insulating shoe if necessary to enter the above areas.


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Chapter V Electric Motor 1 Equipment Specification

Technical specification of 6kV motors

Equipment Description Model Rated Power Current Insulation Power factor

IDF YKK630-4TH 2150kW 244A Class F 0.88 FDF YKK450-4TH 500kW 57A Class F 0.90 Primary air fan YKK630-4TH 1700kW 184A Class F 0.92 Coal pulverizer YHP560-6-TH 520kW 65A Class F 0.83 Motor-driven feed pump 3600kW 400A Class F 0.89 Condensate pump 1000kW 110A Class F 0.83 Circulating water pump YKKL1600-14 1900kW 372A Class F 0.85

C-0 belt conveyor YKK4004-4 355KW 42A 0.86 C-01 belt conveyor YKK4003-4 315KW 37.A 0.86 C-02 belt conveyor YKK4003-4 315KW 37A 0.86

C-03AB belt conveyor YKK3554-4 IP55 250KW 30A Class F 0.85 C-04AB belt conveyor YKK4005-4 400KW 47A 0.86

C-05 belt conveyor YKK355-4 IP55 160KW 18A Class F 0.85 C-06 belt conveyor YKK3553-4 220KW 26A 0.85 C-07 belt conveyor YKK355-4 160KW 18A Class F 0.85

Screw air compressor 200KW 24A 0.85 Coal crusher 560KW 72A 0.80 Fire pump 220KW 26A 0.85

Instrument air compressor 200KW 24 0.85

Service air compressor 200KW 24 0.85 Closed circuit cooling

water pump 315KW 35A 0.87

2 Motor Operation and Maintenance 2.1 General Provisions on Motors

Each motor should carry a rating plate of the original manufacturer on its frame. Don't use a motor not having a rating plate without approval of leaders. A new rating plate should be fabricated according to the data provided by the original manufacturer or test results.

All auxiliary motors should be equipped with appropriate protection. It is not allowed to put a motor having not protection into operation.

All standby motors should be ready for starting at any time. Insulation measurement and periodic rotation operation should be performed if a motor is in standby state for a long term.

The enclosure, ventilation stack, and metal structure of motors should be painted and the rotating parts should be provided with a securely-mounted guard.

For motors with forced oil circulation bearings, the lube oil loss signal and interlock and protective devices should in good order. The protective device should not be deactivated.

The motors and starters should have their frames suitably earthed

The areas around motors should be clean and dry and protected against water, steam and oil incursion. Especially, there is not any obstacle around ventilation ports of motors. The ventilation ports should be free of dust.

The motors should be tested according to the provisions on handover and preventative tests after motor hand-over, overhaul or replacement of coils.


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2.2 Provisions on Motor Operation

2.2.1 Temperature provision

All motors, including HV motors, LV motors, AC and DC motors, should not operate at the rating higher than the ones specified on rating plates in normal operation.

The highest temperature of motor winding and core should be in accordance with the values specified by manufacturers, which should not be exceeded under any operating mode.

The highest temperature of motor bearings should be in accordance with the values specified by manufacturers, which should not be exceeded under any operating mode.

If the values specified by manufacturers are unavailable, the allowable temperature and temperature rise of motor parts shown in the following table shall apply under the continuous rated load and intake air temperature not greater than 40℃.

Insulation class

Measurement Item Test Method Stator

Winding

Rotor Winding Stator core

Slip ring

Sliding bearing

Rolling bearing Wound

rotor Cage rotor

A

Maximum allowable temperature rise

Thermometer method 55 55 60 60 40 55

Resistance method 60 60

Maximum allowable temperature



E







B


Thermometer method 70 70 70 80 80 40 55

Resistance method 80 80 80




F







H







For motors having coolers, the inlet air temperature should not be lower than 5℃ and not be higher than 40℃. For motors with ventilating duct, ventilation dampers shall be appropriately adjusted to limit air inlet flow in winter.


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For the motors with air coolers, the inlet water temperature should not be lower than 5℃ to prevent condensation in air coolers.

When thermometer methods is used to measure motor temperature, an alcohol thermometer other than a mercury thermometer is recommended.

For motors without coolers, run the motors at a reduced load current when the ambient temperature exceeds 40℃. When the ambient temperature drop to below 35℃, it is allowed to raise the load current. For the value of addition, refer to the following table:

Inlet Air Temperature ( )℃ Below 25℃ 30℃ 35～40℃ 40℃ 45℃ 50℃

Change in stator current (%) +8 +5 Rated value -5 -10 -15

2.2.2 Provisions on voltage, current, vibration and shaft play

Motor can run within the range of 95％-110％ rated voltage while the rated output remain unchanged. When the voltage rises up, the current should be reduced correspondingly. When the voltage drops, the current should not exceed 105% the rated value.

When motors run with the rated output, its voltage unbalance value should not exceed 5% the rated value.

For AC motors, the three-phase unbalanced current should exceed 10% the rated value and the current of any phase should not exceed the rated value.

The vibration and shaft play of running motors should not exceed the values shown in the following table:

Rated speed: (rpm) 3000 1500 1000 Up to 750 Vibration value (peak-to-peak value), mm

0.05 0.085 0.10 0.12

Shaft play, mm 2～4 2～4

2.2.3 Provision on insulation resistance of motors

The insulation resistance of LV motors should be measured using 500V megger. The measured insulation resistance should not be lower than 0.5MΩ.

The insulation resistance of HV motors should be measured using 1000V or 2500V megger. The measured insulation resistance should not be lower than 1MΩ/kV.

The insulation resistance of bearing insulating pads for motors should be measured using 1000V megger. The measured insulation resistance should not be lower than 1MΩ.

The insulation resistance must be measured prior to startup of new motors or overhauled motors.

For motors with heaters, the insulation resistance should be measured prior to starting if being out of service for one month or damped.

The insulation resistance should be measured prior to starting if motors without heaters or motors with unused heaters are out of service for half month.

For standby motors, the insulation resistance should be periodically measured in accordance with the Periodic Switching and Test for Electrical Equipments. If the sign of significant moisture or the possibility of decrease in insulation resistance is found, measure insulation resistance on a timely basis and deal with the motors which insulation resistance does not comply with the requirements.

Fro 6kV motors, the insulation resistance measured should not deviate significantly from the previous value if measured at the same ambient temperature. The absorption factor (R60／R15) should also be measured and the measured value should be more than 1.3.


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After measurement, the measurement values should be recorded on a log for future reference.

Don’t start up motors which insulation resistance does not comply with requirements. Under special circumstance, it is allowed to start such motors after obtaining the approval of the chief engineers.

Motors having lower insulation resistance need be dried using the following method;

1) If the motors are equipped with a heater, turn on the heater.

2) Copper loss method: Apply 60~70 % the rated current (DC current) to stator coils and adjust the temperature by changing current amplitude. However, the temperature on motor coil surface should not exceed 75℃.

3) Pay attention to the following points when drying motors:

a.Don’t apply DC current to extremely damp motors to prevent insulation breakdown.

b.During motor drying, place several thermometers at different parts to know temperature and prevent local overheating.

c.Slowly heat the damp motor parts to avoid damage to insulation.

d.Measure the temperature and insulation at an interval of 30 min. When the temperature becomes stable, it is allowed to appropriately extend the interval until the insulation resistance attains a steady value.

3 Motor Patrol Inspection and Maintenance 3.1 Inspection Prior to Motor Startup

Check that no persons work on electrical circuits and mechanical parts, the permits to work have been withdrawn and temporary safety devices have been removed.

Measure the insulation resistance of motors, cables and bearing. The measurement values are not lower than the specified values.

The fans, coupling guard and enclosures of motors are suitably earthed, bolts and nuts are tightened, there is not exposed live part, coolers are free of condensation and foreign matters, and bearing oil level and color are normal. If water is used to cool bearings, firstly put the cooling water system into operation.

Turn the motor rotor by hand to ensure that the rotors rotate freely, no friction and jamming exist between stators and rotors, and the mechanical parts are in good order.

For motors with wound rotors, contact between brush and slide rings is good, the brush is complete and free of swinging and jamming inside brush frames, uniform pressure is maintained between brush and frames, the brush frame is about 3mm away from the slide rings, and the blade switches or contactors used to short-circuit frequency sensitive rheostats are in open position.

The circuit-breakers, fuses and blade switches of the primary circuits are in good order, the operating mechanisms can be operated freely without jamming, and the fuse rating comply with the requirements.

The secondary circuits are in good order, the measuring meters, signal, protection and emergency buttons are in good order and the relaying protection and interlock have been correctly put into service.

3.2 Inspection during Motor Operation

Check that the motor voltage and current don’t exceed the rating and abnormal current rise does not occur compared with the value under the same load.

Check that the motors and driven machines have normal temperature, cable terminals are not overheated, the temperature measuring devices are in good order and no abnormal bearing temperature rise exists.


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The motors are free of abnormal noise, burnt odor and smoke. Periodically clean the motors to ensure that the motors are free of foreign matters, water and steam leakage. Cold air entering motors should be clean and dry. Check that the cooling systems are normally operating.

Check that the bearings are suitably lubricated, lube oil is normally supplied to bearings, oil level, color and oil ring rotation are in good order and forced lubrication systems are normally operating. Replenish the oil with the same designation when necessary.

The motor vibration and shaft play should not exceed the specified values.

The guards, junction boxes and control boxes for motors are in good order;

In case of DC motors or wound rotor type motors, check that slide rings or commutators don't strike fire, uniform pressure is maintained, brushes and leads are complete, not short and not short-circuited to enclosures, slide rings are smooth and free of burnt and discoloration, and the blade switches or contactors used to short-circuit frequency sensitive rheostats are in RUN position.

Check that the relaying protection, secondary circuits and signal indication are in good order.

If any abnormal situation is found, make timely report and analysis to determine whether the motors can continue to run or not. In case of emergencies, stop the motors and then report to shift supervisors.

4 Abnormal Operation and Accident Handling for Motors In case of any of the following conditions, immediately stop the motors, start the standby motors and report to shift supervisors:

Personal injury occurs on motors, power supply circuits or driven machines;

The driven machines are damaged so that it is difficult to sustain operation;

Spark, smoke or fire are found inside the starters or adjusters.

The motors undergo violent vibration, significant shaft play, internal shock, and friction between stators and rotors.

The temperature of motors and bearings sharply rise and exceed the allowable value.

Abnormal noise or speed drop;

Major accidents for which immediate motor stop is required, such as fire and flood which endanger the safe operation of motors.

For key motors, it is allowed to firstly start the standby motor and then stop the failure motors in case of any of the following conditions:

Abnormal noise or burnt insulation odor is found.

Spark or smoke appear inside motors or starters,

The stator current exceeds the rated current and can not be reduced by decreasing the power output,

The core temperature for motors exceeds the allowable value and it is impossible to correct this problem.

The bearing temperature exceeds the allowable value and such problem can not be corrected.

The motors are flooded by water.

During startup or operation, frictions between motor stators and rotors is heard

Three-phase current imbalance exceeds 10%;

Serious ring fire occurs on DC motors and it is impossible to extinguish ring fire.

4.1 Motors Tripped during Operation


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4.1.1 Possible causes

Motors, electrical components or driven machines failure.

DC systems are grounded at two points (in this case, the system is not subject to surge).

The protection or interlock means is incorrectly operated (in this case, the system is not subject to surge).

Power failure etc

4.1.2 Solution

If surge current appears prior to tripping, it is prohibited to re-start motors;

If 6kV motors are tripped in case of emergencies, it is prohibited to re-start it;

If standby motors are automatically put into operation, reset the audible alarm and push all switches to their normal positions;

If standby motors are not automatically put into operation, rapidly close the circuit-breakers of the standby motors and investigate and report the causes of motor tripping to shift supervisors;

It is allowed to re-start the motors only when the cause of tripping is incorrect manipulation, protection failure or voltage loss. In case of key motors without standby ones, it is allowed to restart them if no current surge or significant failure occurs prior to tripping. In case of ordinary motors, stop them for inspection.

Investigate the cause of tripping and keep the record of the operation of protections.

4.2 Motors are Tripped Immediately after Circuit-breakers are Closed

a) Phenomenon

After the closing button is pressed, the motor current sharply rise and then drop to zero, and the red lamp turn on and then turn off.

The audible alarm is active and the green lamp is flashing.

b) Possible causes

Power failure (such as blown fuses and abnormal voltage)

Circuit-breakers and control circuits failure;

Improper operation;

he protection is triggered due to circuit failures;

c) Solution

Inspect electrical and mechanical components;

If all is in order, it is allowed to restart motors once.

4.3 The Quick-breaking or Overload Protection is Triggered when Motors Start up after Installation or Maintenance

a) Possible causes

Mechanical jamming or over-torque

Short-circuit inside motors or cables;

The preset threshold value of quick-breaking protector is too small or the delay time preset for overload protection is too short, etc

b) Solution

Contact instrument personnel

4.4 After motor circuit-breakers are closed, the rotors remain standstill or the speed can not reach


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the rated value, abnormal noise is heard, the motor current is zero or remain at the full scale value of ammeters for more than normal time.

a) Possible causes

Phase loss of one stator circuit (fuses are single-phase blown, circuit-breakers are not three-phase closed, loose contact exists in one phase of blade switches or circuit-breakers, stator windings are single-phase broken).

Broken wire or loose contact exist in one phase of rotor circuits (for example, broken connection between copper bars or aluminum bars of cage rotor and end rings, open connection at soldered joints of wound rotor windings, damaged connection between leads and slide rings, abnormal brushes, opened starter circuits, etc)

Mechanical components of motors are jammed;

Stator winding connection is incorrect (delta connection is changed to Y-connection, one phase is reversely wired in Y-connected winding, etc)

DC armatures are open-circuited, contact between leads and brushes are loose or the brushes are in incorrect position.

The magnetic field of DC motors is open-circuited, contact with resistors is loose or a lead is broken, etc.

b) Solution

Immediately turn off motors;

Turn machines to confirm whether the machines are overloaded. Turn off motors before the machines are turned.

Check whether contact between starting resistors and brushes of wound rotor type motors is loose and armature circuits and field circuits of DC motors are normal or not;

If the machines are in order, check for phase loss, loose switch contact, broken motor wires or incorrect wiring. It is allowed to restart motors only after the causes of problems are investigated and eliminated;

Contact maintenance personnel if the causes of problems can not be found through the above-mentioned check,

4.5 During motor operation, running noise changes, running speed drops and motor current abnormally rise or drop to zero.

a) Possible causes

Phase loss in stator circuits;

System voltage drop;

Turn-to-turn short-circuit, etc

b) Solution

If the motor current does not significantly rise and the machineries run normally, adjust power voltage to the rated value and appropriately reduce the load as possible. It should be noted that the rated current be not exceeded;

If the motor current sharply rises or drops to zero and the operating conditions of machineries change (such as vibration and temperature rise), the motors are running on two phases. In case of key motors, immediately start up the standby motors. In case of ordinary motors, immediately stop them.

4.6 The stator current undergoes cyclic swing during motor operation.

a) Possible causes


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The rotors of cage motors is broken, welded joints are loose, the ends is short-circuited or open-circuited;

For wound rotor type motors, the welded joints of rotor windings are damaged, loose contact or other failures exist in slide ring short-circuiting device or varistors;

The mechanical load experiences uneven change, etc.

b) Solution

Start the standby motors and stop the failure ones;

If there is not standby motors and the relevant measures is ineffective, stop the failure ones;

Stop, inspect and repair the motors.

4.7 Motors are overloaded

a) Phenomenon

The current exceeds the rated value;

The motor enclosures are overheated or have a higher temperature, the coil temperature rise up and a “High Temperature” signal may also be issued.

b) Solution

Attempt to reduce loads so that the current drops to below the rated value;

Start standby motors;

Pay close attention to operating conditions and inspect electrical circuits.

4.8 The motor stator temperature sharply rises and exceed the rated values

Solution:

Check inlet air temperature, ventilation and cooling water system;

Check for blocked ventilation channels and broken fan blades;

Check whether the three-phase current is balanced and the current exceed the normal value;

When motors run at a reduced load, pay close attention to its operating conditions;

If the above-mentioned measures are ineffective, start the standby motors, stop, inspect and repair the failure motors.

4.9 Abnormal Vibration

a) Possible causes

The driven machineries are misaligned;

Friction between moving parts and stationary parts;

Damaged bearings or loose foundation bolts;

Phase loss, etc

b) Solution

If the vibration value is still within the specified range, the motors are allowed to continue operation. If necessary, start the standby motors, report problems and pay close attention to motors.

If the vibration is so violent as to exceed the specified range, immediately stop the motors and then deal with the problems.

4.10 Bearing Overheating

a) Possible causes

Poor lubrication;


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The motor bearings are misaligned or damaged;

The drive belts are excessively tensioned and bearing caps are tightly covered;

The motors are not aligned with driven machineries;

Insufficient oil or deteriorated oil quality, etc

b) Solution

Check whether the bearings are overheated due to abnormal unit vibration;

If a standby motor is available, start it and stop and repair the failure one. If a standby motor is unavailable, pay close attention to operating condition, inspect motors and bearing and report the trouble to leaders.

c) If the temperature continues to rise above the specified value, report such trouble to shift supervisors and stop the motors.

4.11 Slide rings, brush holders and brush frames are overheated during the operation of wound rotor type motors

a) Possible causes

Loose contact between brushes and brush holders;

Unstable brush models;

The brush pressure is too large or uneven

b) Solution

Check for suitable brush designation;

Adjust the brush pressure so that good contact is maintained between brushes and holders;

If the above-mentioned measures are ineffective, start the standby motors, stop, the failure motor and contact maintenance personnel.

4.12 Dealing with Motors Catching Fire

It is necessary to firstly cut off power supply.

Then extinguish fire using CO2, dry powder and 1211 fire extinguishers. It is strictly prohibited to use foam fire extinguishers for electrical fire. Prevent dry powder from entering bearings when using dry powder fire extinguishers,


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Chapter VI DC, Emergency and UPS Power Supply System 1 Equipment Specification for DC Systems 1.1 JZ-BPD-Ⅲ smart battery monitor

1.1.1 General description

JZ-BPD-Ⅲ smart battery monitors are microprocessor-based smart detecting instruments. It adopts AI smart data logging technique and display cell voltage, overall voltage, battery current and temperature and other parameters on a large LCD screen. It is able to transit data information to remote control terminals via RS-232 and RS-422/485 ports.

It is mainly used to detect battery performance in electric power and telecommunication sectors.

Technical Data

Grid frequency: 50Hz±10%

1) Range of voltage measurement:0~3V (0~18V) for battery cells, and 0~300V for storage pack

2) Range of current measurement: 0-1000A (optional sensor)

3) Range of temperature measurement-25~125 °C

4) Measurement error: voltage: 0.5% current: 0.5% Temperature: 2 °C

5) Measurement cycle:<45S

6) Number of detectable channels:1~144 channels

7) Operating mode: Continuous, automatic

8) Product specification: 36 channels for basic models, and 144 channels available upon request

9) Max. power consumption: 50VA

10) Display: 320*240 LCD

11) Communication ports: RS232, RS485

1.1.2 Instruction manual for JZ-LPD-IV smart ground monitors

General Description

DC power sources are used for the control and protective circuits of power plants and transformer substations to ensure safe operation of electric power systems. This power sources are insulated against ground. Single-point earthing of DC feeders will not cause impact on normal system operation. However, the earthing point must be isolated and eliminated, Otherwise, serious accident will occur when another point is grounded.

JZ-IPD-IV smart ground monitors are microprocessor-based smart detecting instruments. It detects insulation resistance between busbar and ground using DC measuring method, balanced bridge and unbalanced bridge. Signal input to DC systems is not required and the measured values are not affected by earth capacity of DC feeders. The ground impedance at positive and negative ends of each branch is accurately calculated from current difference. When the ground resistance is lower than the preset values, an alarm will be generated.

Two types of detecting modes, namely balanced bridge and unbalanced bridge, are provided for JZ-IPD-IV smart ground monitors. The ground resistance of positive busbar, negative busbar and branches as well as the resistance when positive busbar, negative busbar and branches are earthed at a time can be calculated by starting balanced and unbalanced bridges.

JZ-IPD-IV smart ground monitors are able to measure voltage. When busbar voltage exceeds the preset value, a busbar undervoltage or busbar over-voltage alarm will be generated. In addition,


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JZ-IPD-IV is able to store 180 alarm events and to transit data information to remote control terminals via RS232, or RS422/485 ports.

Technical Data


1) Voltage classDC220V

2) Range of ground resistance alarm0~99KΩ

3) Ground resistance resolution1KΩ

4) Busbar voltage error: below 1%

5) Busbar ground resistance error: below 15%

6) Branch ground resistance error: below 20%

7) Number of detectable channels: 0~128 channels (including 2 sections)



10) Display: 320*240 LCD

11) Communication ports: RS232, RS485

12) Number of busbar sections detected2

1.1.3 JZ-MC-Ⅳ monitor unit (V4.01)

I General description

JZ-MC-IV multi-purpose monitor units are microprocessor-based industrial controllers. It adopts AI and fuzzy control techniques. It monitors and displays operating states and parameters of power supply systems on LCDs.

It can receive data, operating parameters and command entered by operators, control the power source systems according to the preset state, transit data information to remote control terminals via RS-232 or RS-485 ports to achieve four remote functions.

Automatic charging management, busbar &branch ground failure check and battery voltage measurement etc are incorporate into JZ-MC-IV multi-purpose monitor units.

It is also able to display circuit-breaker status, overvoltage and undervoltage failures. It has output alarm potential-free contacts and is able to automatically restart after recovery from power failure.

The unit is mainly used for Series GZDW, PEDW DC power source manufactured by Jiuzhou Electric, is able to monitor and control various rectifier module and batteries manufactured by Jiuzhou Electric. In addition, it is also able to control power source products manufactured by other producers after modifying control programs depending on users’ demand.

II Technical Data

Power voltage: 220V±10% (AC or DC)


Control output voltage Uo：-6.5V～+6.5V, 0V～5V

DC input: 0V～5V, 0～25mA, 0～50mA, 0～100mA, 8 channels (including 2 standby channels)

Ground input:

1) Range of ground resistance alarm 0~99KΩ

2) Ground resistance resolution 1KΩ

3) Busbar voltage error below 1.5%


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4) Busbar ground resistance error below 15%

5) Branch ground resistance error: below 20%

6) Number of detectable channels: 0~96 channels (including 2 sections)


8) Number of busbar sections detected 2

Input from battery

1) Range of voltage measurement:0~18V for battery cells, and 0~300V for battery pack

2) Range of current measurement: 0-1000A (optional sensor)

3) Range of temperature measurement -25~125 °C

4) Error: voltage: 0.5% current: 0.5% Temperature: 2 °C

5) Measurement cycle <45S

6) Number of detectable channels:108 channels



AC input: three-phase, four-wire: phase voltage: about 220V, phase current: <5A

Degree of protection: IP20

Display: 320×240 dot matrix LCD

Operation means: keyboard

Communication interface： RS-232, RS-485

1.2 Technical Data of Storage Batteries:

Battery type VRLA battery Cell voltage 2V Floating charge voltage 2.23～2.27 V/个

2.23～2.27 V/cell Equalizing charge voltage 2.3～2.4 V/个

2.3～2.4 V/cell Service life 15 年（25℃）

15 years (25℃)

2 Battery Operation and Maintenance 2.1 Operating Mode of DC Systems

The voltage classes of the DC systems are 110V and 220V, among which DC220V systems are used for drive equipments and DC110V systems are used for control.

DC system wiring:

1) The DC power supply systems of #1 and #2 units adopt sectionalized single-busbar wiring and the one of #3 unit adopts single-busbar wiring. The voltage class is 220V.

2) Sectionalized single-busbar wiring method is used for the DC systems for control of #1, 2 and 3 units. The voltage class is 110V.

3) Sectionalized single-busbar wiring method is used for the DC systems for network control. The voltage class is 110V.

4) Sectionalized single-busbar wiring method is used for the DC systems for coal handling system control. The voltage class is 110V.


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One set of 220VDC system is provided for #1 and #2 units respectively. A bus-tie circuit-breaker is provided between the DC busbar for drive systems of #1 and #2 units so that the two sets of DC systems back up each other. In normal operation, the two sets of DC busbar separately operate. Each set of DC system for drive systems is composed of one set of 1800Ah VRLA batteries (including 104 cells) and one set of HF switching rectifiers (n+1 redundant hot standby, 20A, 220V). One set of 220VDC system is provided for #3 unit and composed of one set of 1800Ah VRLA batteries (including 104 cells) and one set of HF switching rectifiers (n+1 redundant hot standby, 20A, 220V). One set of identical 110VDC system for control is provided for each unit and composed of two sets of 500Ah VRLA batteries (including 51 cells) and one set of HF switching rectifiers (n+1 redundant hot standby, 20A, 110V). One bus-tie circuit-breaker is provided between two sets of DC busbar. In normal operation, the two sets of DC busbar operate separately. One set of identical 110VDC system is provided for network control and composed of one set of 400Ah VRLA batteries (including 51 cells) and one set of HF switching rectifiers (n+1 redundant hot standby, 20A, 110V); One set of identical 110VDC system is provided for the coal handling system and composed of one set of 100Ah VRLA batteries (including 52 cells) and one set of HF switching rectifiers (n+1 redundant hot standby, 20A, 110V).

The HF switching rectifier power supply of each set of busbar operates on busbar in parallel with battery pack power supply. The rectifier charges the storage batteries in floating mode by a small current in addition to normal load.

2.2 Operating Parameters of DC Systems

The DC system busbar voltage should often be the nominal ±5V

The cell voltage should often be 2.25V. Balancing charge should be performed when it is below 2.18V.

The floating charge voltage for battery cells is 2.25V to 2.35V

Insulation resistance:

1) The insulation resistance of batteries should be 0.2MΩ or higher (voltmeter method)

2) The insulation resistance of DC busbar should be 50MΩ or higher (measured with 500V megger)

3) The insulation resistance of DC branches should be 0.5MΩ or higher (500V megger used)

The panels or cabinets should have good insulation performance and a resistance of insulation against ground no smaller than 5MΩ. The insulation resistance between different live parts should not be less than 10MΩ

2.3 Patrol Inspection for DC Systems

2.3.1 Storage battery

The floating charge current of battery packs is appropriate and battery pack is not overcharged or undercharged.

There is not overpowering odor inside the battery rooms and the ventilation and auxiliary equipments are in good order.

The battery rooms are clean, free of foreign materials and have a normal temperature (about 25℃)

Normal lighting facilities and emergency lighting facilities are provided and lamps should be arranged above passages.

The batteries are free of breakage or leakage.

The batteries are not overheated

Battery plates are free of bending, expansion, crack or short-circuiting.


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Each connectors and connecting wires are free of looseness, short-circuiting or earthing, etc.

It is strictly prohibited to use open fire or perform operations which may produce spark, inside the battery rooms. Special fire-extinguishers, such as dry powder ones and carbon tetrachloride ones, should be located at the rooms.

The battery should be kept 0.5m away from heat sources and spark generators. Start up exhaust fans and cut off power supply before replacing bulbs.

HF switching rectifiers

The RUN lamps remain on and the indication is normal.

The output voltage and current are normal;

All components are free of overheating, the connections are not loose and there is not abnormal sound

All fuses are in order and not blown.

The fans of HF switching rectifiers are normally funning.

2.3.2 DC panel

Check that the busbar voltage, floating charge current and load current are normal.

Check that the insulation of DC systems is normal.

Check that the flash apparatus tested operate normally.

Check that all switches and blade switches on DC panels are in correct position.

Check that all lamps mounted on the panels give correct indication and there is not abnormal signal.

Check that no terminal strips and cable terminals inside the panel is overheated

2.4 C. How to Operate DC System:

2.4.1 Precaution for operating the DC system

If parallel connection is required for the DC systems, it is necessary to check for correct polarity and normal voltage difference (not exceed 2 to 3V generally).

If two circuits of power sources supply power to feeders, one circuit is operating and another circuit is as standby in normal operation. Loop closing, loop opening and load changeover operation can be performed only when the bus-tie circuit-breakers are closed.

When two sets of DC busbar have different ground polarity, parallel operation is strictly forbidden.

Batteries must operate in parallel with HF switching rectifier sets. The rectifier sets supply normal load current and battery floating charge current. The storage batteries are used as power source in case of shock load and emergencies.

In normal operation, the DC busbar is not allowed to operate independently from the battery pack.

In case HF switching rectifier set in operation failures, the batteries can separately supply power to the load for a short time. If the failure rectifier sets can not resume normal operation, within a short time, the standby rectifier sets will be put into operation. If it is impossible to put the standby rectifier set into operation, the two sets of DC busbar should be parallel connected so that the rectifier sets of another busbar operate with the two sets of DC busbar.

When one set of HF rectifier set is operating with two sets of busbar, pay close attention to the load, floating charge current and operating conditions of HF switching rectifiers.

Carry out detailed check before a new DC system or overhauled DC systems are put into operation. The relevant inspection records should be available.


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If DC power failure of certain line protection occurs, disable the protection after obtaining the approval from dispatchers. After normal power supply is resumed, enable the protection after obtaining the approval from dispatchers.

Operators should report and record inspection, operation, abnormal conditions and accident handling in detail.

2.4.2 How to put a HF switching rectifier set into floating charge operation

Check that the HF switching rectifier is in order and has received AC power source;

Start the HF switching rectifier and put it into floating charge mode;

Check that the HF switching-mode rectifier is in normal operation

Close the output circuit-breaker for HF switching rectifier

Push the DPDT switches of DC busbar to the busbar charging storage batteries;

Check that the HF switching-mode rectifier is in normal operation

3 Abnormal Operation and Accident Handling for DC Systems 3.1 Abnormal DC Busbar Voltage

a) Phenomenon

An audible alarm is active and the “DC Busbar Failure” alarm window is highlighted;

The “HF Switching-mode Rectifier Failure” alarm window is highlighted;

Low busbar voltage is indicated on microprocessor-based monitor modules.

b) Solution


Check the output HF switching rectifiers and insulation monitors, and use multimeters to determined whether the busbar voltage is lower than the normal value or not.

If the failures of HF switching rectifiers cause abnormal busbar voltage, deal with the problem following 6.3.4;

If the reason is AC power failure, recover AC power supply as soon as possible;

If the measure busbar voltage is normal and low busbar voltage is indicated on the monitor units, contact maintenance personnel.

3.2 HF Switching Rectifier Failure

a) Phenomenon

A “HF switching rectifier failure” alarm is active;

“DC Busbar Voltage Failure” signal may also be issued;

The local “Abnormal” lamp on the panel of HF switching rectifiers turns on.

The output voltage and current of HF switching rectifiers are abnormal;

b) Solution


Check the storage batteries can normally supply power to its load and other rectifiers operating in parallel with the failure rectifier malfunction. If other rectifiers also malfunction, the reasons may be input over-voltage/under-voltage or output over-voltage.

If the reason is the failure of some HF switching rectifiers, put standby HF switching rectifiers into operation, allow the failure one to be out of service and contact maintenance personnel. If many rectifiers failure so that standby rectifiers can not sustain normal operation, allow two sets of DC busbar to operate in parallel with each other, isolate the failure rectifiers and contact maintenance


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personnel.

After failures have been cleared, put the HF switching rectifier into operation and return to the normal operating modes.

3.3 DC Systems are Grounded

a) Phenomenon

An audible alarm is active and the “DC Busbar Failure” alarm window is highlighted;

An alarm signal and insulation resistance of failure branches is indicated on the microprocessor insulation monitors.

Measure the voltage of positive and negative DC busbar to ground.

b) Solution


Operators should, according to information indicated on the insulation monitors, record and report the No. of grounded branch or branch with reduced insulation as well as branch power source to shift supervisors, and contact maintenance personnel.

If the reason for grounding is that maintenance personnel works on DC circuits, immediately stop works to eliminate grounding.

If grounding results from emergency lighting circuits, firstly cut off power supply, report the causes to shift supervisors and contact maintenance personnel;

Check whether any equipment is started or shut down. If YES, carefully check such equipments.

Firstly check defective equipments or equipments operating in worse environments.

Power supply is cut off for troubleshooting after obtaining the approval from shift supervisors and concerned persons.

Troubleshooting for DC system ground failures should be performed by maintenance personnel under the uniform leadership of shift supervisors. Operators should coordinate with maintenance personnel in this regard. If troubleshooting concerns equipments managed by dispatchers, firstly obtain the agreement from dispatchers.

3.4 Treatment for other Failures

If a fuse at battery pack output is blown, firstly check rectifier panels, then check interconnecting cable between battery pack and at output terminals. If no problem is found, replace the fuse once. If the new fuse is blown again, don't continue to replace the fuse, but report such situation to shift supervisors and inform maintenance personnel. Wear protective gloves when replacing fuses.

No indication on voltmeters: If operators find that no indication is given on the voltmeters of rectifiers, battery or DC busbar, firstly check for busbar voltage loss using an electroscope. If the reason is not busbar voltage loss, check circuit voltage and voltmeter fuses. It is impossible to clear failures, report to shift supervisors and contact maintenance personnel.

If no current is output from the rectifier panel, firstly check battery packs and then DC busbar. Turn off HF switching rectifier modules and carefully investigate the causes of failures. If it is impossible to clear failures, report such failures to shift supervisors and contact maintenance personnel. If it is expected it will take a long time to clear failures, close the bus-tie circuit-breakers so that the standby power source take over the load.

If the fuses at battery output are blown and DC busbar voltage loss results from rectifier panel tripping, immediately report such problem to shift supervisors and put standby HF switching rectifiers into operation. In case the standby one can not be put into operation, close the bus-tie circuit-breakers so that another (sectionalized) busbar takes over the load

When a feeder circuit-breaker is tripped, don’t supply power until the causes have been investigated


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and appropriate measures have been taken.

4 Emergency Power Supply 4.1 Technical Data of Diesel-engine Generator

Detailed Technical Data of WILSON P900E1 Diesel-engine Generator

Power Generating Set Data Diesel Engine Data Generator Data Model of Power Generating Set

P900E1 Model of Diesel Engine 4006TAG3A Model of power generator

LL7024P

Apparent power output reserve

900KVA Max. power output 786KW Excitation method

Brushless self-excitation

Active power output reserve

720KW Number of cylinders and cylinder arrangement

6 cylinders, inline Voltage regulation

AVR

Continuous apparent power output

800KVA Cylinder bore 160mm Voltage, phase 380V ， 3 phases, 4 wires

Continuous active power output

640KW Stroke 190mm Current 1368A

Speed 1500 rpm Capacity (displacement)

22.9L Power factor 0.8 (lag)

Oil consumption at power reserve and full load (640kW)

190 L/hr Exhaust air flow 1182 m3/min Degree of protection

IP23

Oil consumption at continuous power and full load (584kW)

170 L/hr Fuel gas consumption 73 m3/min Insulation class

Class H

Overall length 4283mm Smoke exhaust flow 193 m3/min Frequency 50Hz Width 1912mm Exhaust fumes

temperature 500OC Brand Leroy Somer

Height 2286mm Air intake method: turbo supercharging, air-to-air cooling

Place of origin and manufacturers

FG Wilson of UK

Net weight 6259kg Cooling method With fans and water tanks, closed circulating water cooling

Noise 97dB or lower

Starting mode: Through 24V battery

Place of origin and manufacturers

FG Wilson of UK

Total machine oil capacity

123

Total cooling water capacity

105

Speed governing Electronic governor Oil spray mode Mechanical

spraying

Oil tank 1671L Place of origin and

manufacturers Perkins-Rolls-Royce of UK

4.2 Patrol Inspection for Diesel-engine Generators

The diesel-engine generator rooms are clean and free of ponding water and the lighting and ventilation facilities are in order;

The generator body is clean and free of foreign matters;

The electrical control panels are clean and all status indication and alarm window indication are normal;

The battery voltage is normal and the electrolyte level and specific gravity are normal;


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All protections are put into service and are in reset states;

The water heaters, oil heaters, water circulating pumps and oil circulating pumps are in normal operation and all parameters are normal;

The pressure in air receivers, oil level in fuel oil tanks and water level in cooling water tanks are normal;

The batteries are normally charged and the charging current is within the specified range;

The diesel engines are free of oil leakage.

The diesel-engine generator end caps are clean, the ventilation facilities and cable connections are in order;

Carefully check the diesel generating set to confirm that they are ready for startup at any time.

4.3 Main Steps for Routine Diesel generating set test

Check that the diesel generating set is in standby state.

Check that the emergency ON lamp of diesel generating sets turn on;

Check that the spare power circuit-breakers of the protective sections are in AUTO position;

Push the generator control mode selective switch to the TEST position;

Check that the diesel-engine generator successfully starts up and the speed, voltage and frequency are normal;

Check that the generator output circuit-breakers and standby power switch of the protective section are properly closed.

Check that the three-phase current of the diesel-engine generating sets is zero

Check that the three-phase voltage at the diesel-engine generating set output is balanced;

Check that all generator parts are in normal operation and no abnormal signal is sent;

Press the emergency stop pushbuttons of the diesel generating sets:

Check that the generator output circuit-breakers and standby power switch of the protective section are properly opened;

Check that the diesel-engine generator stops operations

Push the generator control mode selective switch to the AUTO position;

Check that the diesel generating sets are in standby state and the output circuit-breakers store energy properly;

4.4 Start and Stop Mode of Diesel Generating Sets

4.4.1 Automatic start

Push the control mode selective switch to AUTO, press the emergency ON pushbutton and check that the emergency ON lamp turns on, the operating power supply to 380V protective section is missed and the diesel generating set automatically starts up.

4.4.2 Automatic stop

After the generating set has run, push the stop mode selective switch to AUTO. When 380V power supply is resumed, the diesel generating set output circuit-breakers are tripped, the operating power circuit-breakers are closed and therefore automatic changeover is accomplished. Then, the diesel generating set automatically stops and is in standby state.

4.4.3 Manual start

Push the control mode selective switch to MANUAL and start the diesel engine using the START pushbutton and handle on the diesel engine. After startup, the diesel generating set will automatically operate at rated parameters.


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4.4.4 Manual stop

When the STOP pushbutton is pressed, the diesel generating sets will automatically stop.

4.4.5 Test start

Open the generator output blade switch, push the control mode switch to the TEST position and simulate protective section power failure to check whether the diesel generating set can automatically start. After the operating power is restored, the generating set should automatically stop. After the completion of the test, reset the control mode switch to AUTO, close the generator output blade switch so that the diesel generating set is in standby state again.

4.4.6 Test stop

If the diesel generating set is still in operation after the completion of the test, press the STOP pushbutton to stop the diesel generating sets.

4.5 Main Steps for Returning Diesel Generating Set to Standby State

All diesel generating set works have been completed and the generating sets are ready for operation.

Check that all diesel-engine generator components are in good order and the auxiliary and control power has been supplied to the diesel generating sets;

Put the water heaters, oil heaters, water circulating pumps and oil circulating pumps in operation. All parameters reach the specified values;

Start the air compressors and raise the pressure in air receivers up to the specified value;

Put the battery chargers into operation and check that the charging voltage and current are normal;

Put the diesel-engine generator excitation into service;

Check that all fuses are mounted inside the electrical control panels of the diesel generating sets;

Return the circuit-breaker at the diesel-engine generator output to standby state.

Return the spare power branch switches of the diesel generating sets to the standby state;

Put the low-voltage protective switches into service;

Pull out the mechanical generator starting latch;

Push the local, manual starting handle of the diesel-engine generator to the intermediate position

Mount the fuse for the diesel-engine generator output circuit-breakers and check that the circuit-breakers store energy properly;

Put the emergency devices of diesel-engine generator into service and check that the emergency ON lamps turns on;

Push the generator control mode selective switch to AUTO;

Check that the status indication on electrical control panels and alarm window are normal;

4.6 Main steps for parallel operation with the protective section after the diesel-engine generator has been manually started

Check that the diesel generating sets are in standby state.

Push the generator control mode selective switch to MANUAL;

Manually start up the diesel generating sets and check that the speed, voltage and frequency are normal;

Press the pushbuttons to close the generator circuit-breakers and check that the red closing lamp of the circuit-breakers at the diesel generating set output turn on;

Confirm that the standby circuit-breakers are in open position, and close the standby circuit-breakers sequentially.


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Open the operating power circuit-breakers;

Check that the standby power circuit-breakers have been closed and the red lamps turn on;

Check that the diesel generating sets and protective sections are in normal operation.

5 AC UPS System One set of the UPS manufactured by Qingdao LDC Technology Inc. is provided for each unit. It is able to supply stable power to local microprocessors, I&C protections, DEH and other key consumers.

5.1 Main Technical Data of the UPS

a、Technical parameters of rectifiers:

Input Voltage 380 / 400 / 415V

Range of input voltage -20%~+30%

Input frequency 50 / 60 Hz ± 7%

Input power factor 0.9

Normal input current (A)

18 17 16

27 26 25

36 34 33

54 51 49

72 68 66

90 86 82

108 103 99

144 137 132

180 171 165

216 205 198

288 274 264

Max. input current (A)

23 21 20

34 32 31

45 43 41

68 64 61

90 85 83

113 107 103

136 129 124

180 171 165

225 214 206

270 256 248

360 343 330

Soft activation 15% ～ 100% : 15 sec

Efficiency 99% Voltage regulation rate

±2V

Limit current (A)

27 26 24

41 39 38

54 51 50

81 77 74

108 102 99

135 129 123

162 155 149

216 206 198

270 257 248

324 308 297

432 411 396

Ripple voltage 0.5%

b、 Inverter

DC input range 165～270VDC/83～135VDC Waveform Sine wave Output voltage 220 / 230 / 240 V 1 PHASE Output power factor 0.8 100% on-load voltage regulation ±1 %

Range of frequency lock frequency 45 ～ 55 Hz / 55 ～ 65 Hz

Output frequency (for normal starting ) 50 / 60 Hz ±0.01%

Harmonic voltage distortion (linear load) < 2 %

Overload state

≤110% Continuous 110～125% 10 min

125～150% 1 min

≥ 150% 10 sec


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100% load efficiency 92% 92% 93% 93% 93% 93% 93% 94% 94% 94% 94% Max. output limit current (A) 132 193 260 390 520 650 780 1044 1308 1560 2088

c、 Static bypass

Voltage range ±15% (LINE TO NEUTRAL) Frequency range 45 ～ 55 Hz / 55 ～ 65 Hz Efficiency 99.5% KVA 10 15 20 30 40 50 60 80 10

0 120

160

Change-over time: Mains supply-> Inverter ≤0.4 ms Inverter-> mains supply ≤0.4 ms

Manual bypass Electronic protective devices are used and power is uninterruptedly supplied.

Isolated output Isolated

d、 UPS characteristics

Overall efficiency 89% 89% 90% 90% 90% 91% 91% 91% 91.5% 92% 92.5% Working environment: Temperature -10 ～ 40℃ ( 32 - 104℉ ) Humidity (20 )℃ 0% - 90% (non condensing) Height 1500m above sea level Max. heat dissipation (kW) 0.65 0.95 1.3 1.9 2.6 3.0 3.5 4.6 5.5 6.5 9.0 Weight (kg) 350 460 500 730 900 1060 1200 1500 2000 2500 3000 Height (mm) 1800 Depth (mm) 800 Width (mm) 600 1200 1800 Noise < 65 dBA (at one meter from the front surface of the box) Standards: -CE Compliant -EN50091-1，-2 Compliant -FCC CLASS A Compliant Protective circuits: Short-circuit protection Rectifier, standby power source unit and bypass switch Lightning protection MOV EMC filter I/O Output isolation I/O &bypass totally isolated LCD display YES Indication & alarm: LED. LCD and buzzer YES Potential-free contacts YES Battery activation YES

5.2 Main Characteristics of the UPS

1) Reliable input protection:

Air switches are mounted in all input circuits. When inverter or load failures cause circuit-breakers to be tripped, power can be continuously transmitted via other circuits.

2) Input surge protection

A MOV surge protector is mounted at input end. Therefore, the UPS and its loads are protected against lightning and surge current generated by nearby loads.

3) Effectively suppressing EMI:

In order to conform to international standards concerning EMC, EMI filters are mounted on the UPS


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to significantly reduce EMI and prevent other equipments connected to the same AC input source from any adverse effect.

4) High-efficiency AC/DC design:

The phase control technology is applied to regulate DC busbar voltage and ensure that the power supply is clean. In addition, more durable SCR assemblies and input inductors are used to avoid AC power supply waveform distortion

5) F DC/AC design:

Inverters adopt high-efficiency IGBT modules and PWM techniques so as to convert DC voltage to AC voltage. Therefore, the number of modules used is decreased, the reliability is effectively improved, and the size and weight of the entire UPS are greatly reduced. The UPS quality is considerably improved and the operating noise is also greatly reduced.

6) Isolated I/O design:

Isolating transformers are mounted at the I/O of UPS. This does not solve the problems caused by poor input AC voltage but also effectively eliminate the effect of ground current and facilitate the connection of UPS with other equipments. In addition, the two sets of isolating transformers can ensure that the UPS and its load can continuously and efficiently operate in dangerous electrical environment, such as lightning.

7) Plug and Play design

The circuits are composed of several modules inserted in the UPS. These modules can be easily removed, repaired or replaced. Therefore, they may be called plug and play modules.

8) Cold starting function:

The UPS unit can be started without mains supply. That is to say, if the UPS has storage batteries (options), the UPS unit can be started through the batteries (if the UPS is used together with the DC power source provided by the power plant, the DC power source start UPS). The use of current-limiting circuit may avoid problems of other many brands (when the batteries are directly connected with DC busbar having no current, transient surge current may cause damage to air-breakers and DC capacitors at battery ends)

9) User-friendly design;

The design of the UPS take account of the methods used to protect it against incorrect operation. For this reason, a air-breaker sensor and power supply sensor are mounted in circuits. Therefore, any improper operation will not cause damage to the UPS.

10) Wide input voltage range (380VAC / -20%~+20%)

The design of the UPS takes full account of bad power supply quality in certain areas in China. In order to further improve the safety and reliability, the range of input voltage is further widened. Meanwhile, all input components are carefully selected to suit to shock by extreme high voltage and large current.

11) Outstanding adaptability to worse environments:

All UPS components are high-efficiency and high-safety ones, therefore, the UPS is able to normally operate in worse environments, such as worse temperature and humidity, some height above sea level or earthquake.

12) Parallel-connected power source design:

Static switching power supply adopts parallel connection method. Power supply to the loads will not be affected no matter which condition occur in the UPS.

13) Easy panel operation

The UP/DOWN/EXECUTION switches are mounted on the front panel and the LCD can be easily


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operated using display controls. Some key inverter switches are located behind the front door panel and can be operated after opening the front door (the front door is opened using a key. If a key is unavailable, it is possible to operate inverter switches by entering a keyword and then accessing windows) t prevent unauthorized access to UPS controls.

14) Recording capacity:

In order to provide the information for users for reference, information and time of each event are stored in the UPS. Therefore, users can know any conditions of UPS. Information stored in the UPS will not be cleared even throughout power failure.

15) Long Mean Time between Failures (MTBF)

Before mounted into the UPS, each components are strictly tested. Each component operate at reduced rating value to ensure high reliability and high efficiency. The MTBF calculated in accordance with MIL-HDBK-217E, RELIABILITY PREDICTION OF ELECTRONIC EQUIPMENT, is 250,000 hours.

16) Emergency stop device:

In case of emergencies, such as short-circuit fire or earthquake, inverters can be stopped by means of emergency stop switches or smoke detectors (upon customer’s request) so that there is not AC power at transmission end and the loss can be minimized.

17) System architecture


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MAINS

INPUT

380/

400/4

15V,

50Hz

3P3W

BYP

ASS IN

PUT

220

/230V,

50Hz

1P2W

BATT

ERY I

NPUT

220V

/110V

OUTPU

T

220V/

230V

50Hz

1P2W

3T1

3Q1

3Q2

3KM3

3T2

3A13A2

3KM2

3Q5

3Q4

3Q3

3L1(3L2)

3L3

UPS Architecture (core components shown only)

18) The UPS systems are composed of the following parts:

Mains power input circuit-breaker without fuses 3Q1 (Input Breaker )

Bypass power input circuit-breaker without fuses 3Q3 and 3Q4 (Input Breaker )

Battery input circuit-breaker without fuses 3Q2 (Battery Input)


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- Output circuit-breaker without fuses 3Q5 (Output Breaker)

- Input Filter & Protection Network;

- Rectifier 3A1 (rectifier);

- Inverter 3A2 (inverter)

- Static switch 3KM2 and 3KM3 (Static Switch)

- Isolation transformers 3T1 and 3T2 (Isolation Transformer)

- Output filers, etc

When a normal mains input is available, AC voltage is converted into DC voltage into the inverters and loads (if the optional chargers are able to charge battery packs under normal operating mode). In case of mains power failure, the DC power source unit provided by users or optional battery packs supply power to the consumers.

19）The front panel is located at the upper part of circuit board boxes and operators can view all status indication. Switches and keys are provided to operate and set the UPS. The functions of panel-mounted controls are described below:

Ａ：LCD display: The LCD display current status and historical information. The UPS parameters, current time, inverters and buzzers may be set by means of the LCD. The LCD is provided with back-lit LEDs. The LEDs will turn off after the UP/DOWN/ACK keys are not pressed for 3 min., and turn on when any of the UP/DOWN/ACK keys is pressed.

Ｂ：Status LEDs: 24 LEDs indicate the current status of the UPS and provide users with latest information. When an abnormal condition exists, certain LEDs will turn on. The 24 LEDs are as follows:

INVERTER ON－Inverter in operation

INVERTER SS－The static switch for standby power source is opened, static inverter switch is activated and the inverters supply power to the loads.

SHORT CIRCUIT－The UPS output is short-circuited.

FUSE／OVER TEMP SD－The inverters are locked due to a blown fuse or high temperature.


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INVERTER FAIL SHUTDOWN－The inverters are shut down due to a abnormal output voltage.

BYPASS ON SHUTDOWN－While the inverters are in execution, the bypass switch without fuses is activated and causes the inverters to be shut down.

HIGH DC SHUTDOWN－While the inverters are in execution, a excessively-high DC voltage causes the inverters to be shut down.

OVERLOAD SHUTDOWN－When the output load exceeds the rated value, the inverters are shut down. The UPS will be activated again 7 seconds after the load is reduced.

70%LOAD－The UPS is connected with a load exceeding 70% nominal value.




RESERVE AC FAIL－The standby AC power voltage is out of range.

RESERVE FREQ FAIL－The frequency of the standby AC power source is out of range.

BATTERY LOW－The DC power voltage (or battery voltage) is below 180VDC so that the inverters will be shut down

BATTERY LOW SHUTDOWN－The DC power voltage (or battery voltage) is below 165VDC (lower than the DC voltage acceptable to the inverters) so that the inverters are shut down.

RECT AC FAIL－The voltage of mains input to the rectifiers is out of range.

ROTATION ERROR－The phase rotation of mains input to the rectifiers is incorrect.

RECTIFIER SHUTDOWN－The DC power voltage is so high (exceeding 295VDC) that the rectifiers are shut down. The rectifiers will be automatically activated again 30 seconds after a failure is cleared.

HIGH DC－ When the DC voltage exceeds 285VDC, the voltage-limiters of the UPS will be activated so that the voltage does not continue to rise up.

BOOST CHARGE－The batteries are charged in equalizing charge mode.

BATTERY TEST－Battery test is in progress.

EMERGENT STOP－The emergency stop is activated so that the inverters are shut down.

DATA LINE－The LED is flashing, indicating that information is transmitted via communication ports.

Ｃ：alarm LEDs: In case of abnormal conditions, an alarm LED will turn on and users can know the error information indicated by the LED. When the UPS restore normal conditions, the LED will turn off. The meaning of each LED is described below:

RECT AC FAIL－The AC input to rectifiers is abnormal (such as out-of-range AC input voltage or phase rotation error) so that rectifiers are shut down.

RESERVE FAIL－The standby AC input is abnormal, such as out-of-range AC input voltage or frequency.

FUSE／TEMP－The inverter fuses are blown or the inverter temperature is too high.

OVERLOAD－The output load exceeds 110%, 125% or 150% the nominal value.

HIGH DC－When the DC voltage exceeds 285VDC, the LED will turn on.

BAT LOW－When the DC voltage is below 180VDC, the LED will turn on.


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BAT LOW STOP－When the DC voltage is below 165VDC, the inverters can not be activated and the LED will turn on.

FAULT－The inverters is shut down due to an abnormal condition, such as overload, short-circuit, high DC voltage, blown fuse/high temperature, opening of bypass switches or sudden stop,

These LEDs are located behind transparent glass and operators can view them without the need for opening door panels.

Ｄ、Buzzers sound:

Ｅ．Bypass LED: When the service bypass switch is activated, the LED will turn on. When the service bypass switch is activated, it is impossible to activate the inverters. If the inverters are in operation, it will be immediately shut down.

Ｆ．Standby power LED: When the standby power switch is activated, the standby power source unit will take over power supply to the load and the LED will turn on.

Ｇ．Rectifier LED: When the rectifiers are in normal operation, the LED remains On, indicating that the input power voltage and phase rotation are correct, the rectifier switch is activated and the DC busbar voltage is normal.

Ｈ．Power Failure LED: When the UPS is in power failure state, the LED will turn on. The LED may be used to indicate the result of battery tests. If battery tests fail, the LED will flashing until operators replace batteries, even when normal power supply is available.

Ｉ．Inverter LED: when the inverter switch is activated, the LED will turn on. The LED indicates whether the inverters are in operation or not.

Ｊ．Static inverter switch LED: When the static inverter switch becomes activated and static standby power switch becomes off, the LED will turn on and the inverters supply power to the loads. The LED generally turns on about 7s after the static inverter switch is activated.

Ｋ．Static standby power switch LED: When the static standby power switch becomes activated and static inverter switch becomes off, the LED will turn on and the standby power sources supply power to the loads. Because the static standby power switch and static inverter switch can not be on at a time, the static inverter switch LED and static standby power switch LED will also turn on at a time.

Ｌ．Output LED: When there is AC voltage at output terminals, the LED will turn on. This is an important indication which helps users to determine the availability of AC output

Ｍ．UPWARD key: if is a LCD control key. When UPS information or commands need be reset, it moves the cursor upwards to the desired items or change numerical values/attributes.

Ｎ．DOWNWARD key: if is a LCD control key. When UPS information or commands need be reset, it moves the cursor downwards to the desired items or change numerical values/attributes.

Ｏ．ACK key: it is a LCD control key which can be used as a Page Down key and used to confirm chosen number/ attribute/ items.

Ｐ．Inverter activation switch: It is a switch used to activate inverters. When the key is pressed together with the inverter control switch (Q), the inverters are activated.

Ｑ．Inverter control switch: It is a inverter control switch. When the key is pressed together with the inverter activation switch (R), the inverters are activated; When the key is pressed together with the inverter off key (R), the inverter will be cut off

5.3 Startup

5.3.1 Perform the following check prior to startup

Check that the input voltage is within the rated input voltage range.


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Check that the input frequency is within the rated input frequency range.

Check that the sequence rotation of input power is correct.

Check that all load switches at output ends are in open position.

Check that all air-circuit-breakers and changeover switches on DC panels are in open position.

Check that foreign matters are removed from inside the UPS.

5.3.2 Normal starting procedure

Close the RESERVE air switches. At this point, the reserve power source (F) and output (L) LEDs turn on, power has been supplied to the static reserve power switch circuit, output ends and the UPS and the fans begin to run.

Close the RECTIFER air switch, If the input power has a correct phase rotation, the rectifiers will be automatically activated and DC busbar voltage will be slowly built up (15 to 30 seconds) After the DC busbar voltage has been built up, DC voltage may be supplied to inverters and the rectifier (G) LED will turn on.

Close the BATTERY switch: for the sake of safety, a fuse link is mounted between the DC panel and DC busbar voltage to avoid abnormal situations. When the BATTERY switch is closed and the rectifiers can not supply DC power to inverters, DC electric energy will be immediately supplied to inverters.

Press the inverter activation switch: In order to activate inverters, the inverter activation switch (P) must be pressed together with the inverter control switch (Q). The inverters will build up voltage at its output and the inverter (I) LED will turn on about 7s after it is put into operation. After another 3 seconds, the static switch will automatically change output load from reserve power source to inverter output, and the static switch (J) LED will turn on. Now, the UPS has been put into operation.

Close the UPS OUTPUT air switch.

Check that the indication on LCD is correct: all alarm LEDs on the right side of the panel should remain Off and the two LEDs (“INVERTER ON” and “INVERTER SS”) on the left side should remain On.

5.4 Shutdown

5.4.1 General shutdown procedures

When the system is in normal operation, shut down it observing the following procedures: Press the inverter off switch (R) together with control switch (Q). In this case, the static switch will automatically make the reserve power source to take over the load from inverters. The output voltage interruption will not occur.

5.4.2 Complete shutdown procedures

When the system is in normal operation, shut down the complete UPS using the following procedures:

Open the UPS OUTPUT air switch: firstly determine that the output load is not in use, before opening the output air switch. No power output will exist and the equipments will be damaged if the output air switch is opened when the output is in use. After the output air switch is opened, the voltage is unavailable at output (or load).

Close the inverter switch: in order to shut down inverters, it is necessary to press the inverter off switch (R) and inverter control switch (Q) at a time. In this case, the static switch will cause the reserve power supply take over the load and the interruption of output voltage will not occur.

Open the BATTERY switch: if all UPS power sources need be totally turned off, please continue to open the BATTERY switch so that the rectifier can store energy in DC busbar only.


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Open the RECTIFIER air switch: After the rectifier air switch is opened, the rectifier can not build up DC power supply to DC busbar form mains input and the DC busbar will slowly release electrical energy. The electric energy will be completely released after about 5 min (below 20VDC).

Open the RESERVE air switch.

All power sources have been turned off, LCD and LED turn off and the UPS is totally shut down.

5.5 Load Changeover to Service Bypass

If the UPS need be repaired and maintained, change over the UPS to service bypass mode.

Before changeover to the service bypass, please confirm that mains supply takes over the load.

Shut down the inverter: in order to shut down inverters, it is necessary to press the inverter off switch (R) and inverter control switch (Q) at a time. In this case, the static switch will cause the reserve power supply take over the load and the interruption of output voltage will not occur.

Open the BATTERY switch: if all UPS power sources need be cut off, firstly open the BATTERY switch so that the rectifier can store energy in DC busbar only.

Open the RECTIFIER air switch: After the rectifier air switch is opened, the rectifier can not convert AC voltage to DC voltage to DC busbar and the DC busbar will slowly release electric energy. It takes about 5 min to completely release the electric energy (below 20VDC).

Close the service bypass air switch: When the bypass air switch is closed, the reserve power air switch and reserve power static switch are still in closed state. Because the bypass circuit has a low impedance, the power source will be changed over from reserve power circuit to bypass circuit and power is uninterruptedly supplied to the load.

Open the RESERVE air switch: now, the reserve air switch may be opened to release electric energy from the UPS. Therefore, no electric energy exists inside the UPS and the safety of maintenance or repair personnel can be ensured.

Open the UPS OUTPUT air switch: in this case, the output LED will turn off and the loads are fully disconnected from inverters so that power can not be supplied from the load to inverters.

5.6 Change over the load from service bypass to inverters

Close the RESERVE power air switch. At this point, the reserve power source LED turns on, electric energy exist in the static reserve power switch circuit and the UPS and the fans begin to run.

Close the UPS OUTPUT air switch. Electric energy exists in the output.

Open the service bypass air switch: When the bypass air switch is in closed state, never close the inverter switch (because the CPU will check that AC power is supplied to the air switch, in order to prevent direct connection between mains input and inverters). If the bypass air switch is opened after the reserve source air switch is closed, the reserve source circuit will continue to supply power and AC output is not interrupted.

Close the RECTIFER air switch, if the input power has a correct phase rotation, the rectifiers will be automatically activated and DC busbar voltage will be slowly built up (15 to 30 seconds) After the DC busbar voltage has been built up, DC voltage may be supplied to inverters.

Press the inverter activation switch: In order to activate inverters, the inverter activation switch (P) must be pressed together with the inverter control switch (Q). The inverters will begin operation. Inverter output building-up is completed about 7s After another 3s, the static switch will automatically change output load from reserve power source to inverter output. Now, the UPS has been put into operation.

Close the BATTERY switch: For the purpose of increased safety, a fuse is used between the DC panel and DC busbar to protect against danger due to an abnormal condition. When the rectifier malfunctions, the DC panel will supply DC voltage to inverters immediately.


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Check for correct LCD display: Change over LCD menus to check whether the indication on LCD is in accordance with the actual situation and an alarm is active.

5.7 Operating mode:

The UPS may be operated under four different operating modes, namely normal mode, backup mode, reserve power mode and service bypass mode.

5.7.1 Normal mode

MAINS INPUT3×400V,50Hz3P3W

BYPASS MAINS1×230V,50Hz1P2W

BATTERY INPUT220V/110V

OUTPUT1×220V/230V50Hz1P2W

3T13Q1

3Q2

3KM3

3T23A1 3A23KM2 3Q5

3Q4

3Q3

3L1(3L2) 3L3

When normal mains input is available, rectifiers convert AC voltage into DC voltage, supply DC voltage to inverters and charge batteries (when provided with a charger). During conversion, the rectifiers can eliminate surge, noise and unstable frequency in mains input and therefore ensure that inverters can supply stable and clean power to the load.

5.7.2 Battery backup mode





3T13Q1

3Q2

3T23A1 3A23Q5

3Q4

3Q3

3L1(3L2) 3L3

3KM3

3KM2

When mains input fails, the DC power source will rapidly replace rectifiers to supply DC input to inverters. Therefore, the AC output converted by inverters will not be interrupted and the load connected with the output can be well protected.

5.7.3 Bypass reserve power mode





3T13Q1

3Q2

3T23A1 3A23Q5

3Q4

3Q3

3L1(3L2) 3L3

3KM3

3KM2

When an inverter failure, such as overtemperature, short-circuit, abnormal output voltage or


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overload, occurs, the inverters will automatically stop operation. If the mains input is abnormal, the static switch will be changed over to the reserve power output for use by the load.

5.7.4 Service bypass mode





3T13Q1

3Q2

3T23A1 3A23Q5

3Q4

3Q3

3L1(3L2) 3L3

3KM3

3KM2

If routine maintenance of the UPS is required or the DC panel provided by power plants need be replaced and the output can not be interrupted, users may firstly stop inverters, close the service bypass air switch and then open the rectifier and bypass air switches. Thus, AC output supplied to the load will not be interrupted during this changeover. No AC or DC voltage exist in the UPS except for the output transformers, therefore ensuring the safety of maintenance personnel.

6 Operating environment of UPS: The UPS should operate at a ambient temperature smaller than 25℃ and relative humidity smaller than 80%.


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Chapter VII Protection and Automatic Device 1 General Provisions on Protections and Automatic Devices

The new relaying protection and automatic devices must be accomplished with complete drawings (schematic drawings, exploded drawings, installation drawings and setpoint lists etc). The protective modules, relays, test elements and secondary terminals must be clearly and correctly marked, the alarm window signals are in order and the texts are legible.

When primary equipments are put into operation, the relevant protections should be enabled. If the protections can not be enabled due to failures, it is prohibited to put primary equipments into operation. When primary equipments are used as hot standby, the relevant protections should be enabled. When primary equipments are used as cold standby, it is no necessary to stop protections. Relaying protections and automatic devices for equipment in operation shall be in accordance with the actual situations.

The drawings for relaying protections and automatic devices must be in accordance with the actual situations and all modification to secondary circuits and wirings should be recorded on the relaying protection logs by professional personnel.

Startup and shutdown of relaying protection and automatic devices as well as operations on the protection secondary circuits must be subjected to the approval of dispatchers or shift supervisors.

Operators should not work on secondary circuits. When inspecting and dealing with defects in circuit-breaker control and signal circuits, it is strictly prohibited to remove secondary wirings.

Before relaying protection personnel commence works on protection and secondary circuits, operators must review permits to work and safety measures. Before the set values or secondary wiring is modified, obtain set value notices, reports and drawings approved by the relevant departments. Operators should check equipment conditions against permits to work and take safety actions. If any work may cause malfunction of the protection, operators must take appropriate measures to prevent protection malfunction.

After relaying protection personnel have completed their works, operators should check that wirings, protective elements and marks previously removed have been replaced, links are in correct positions and works are clearly recorded on relaying protection logs.

In order to prevent protection malfunction during equipment operation, it is not allowed to perform any work which may cause relaying protection panel vibration, such as drilling. If necessary to perform such operations, it is necessary to take appropriate measures or disable instantaneous protection.

When relaying protection personnel finds any abnormal condition (such as DC system grounding) or circuit-breaker tripping, operators should immediately urge protection personnel to stop operation and remain systems at current state. After the causes have been investigated and is deemed not to be associated with the operation, it is allowed to continue such operation.

It is not allowed that transformer gas protection is out of service together with differential protection. Either transformer gas protection or differential protection may be out of service after obtaining approval from dispatchers or shift supervisors. When both differential protection and gas protection are put into operation at a time, the backup protection may be out of service for a short time if approved by dispatchers.

After works on differential protection's AC circuits are completed, operators can enable differential protections only when receiving notices from relaying protection personnel.

The following check should be performed if a protection need be enabled during normal operation.

(1). For operational relaying protections, records indicating that they can be put into operation should be available on protection logs.

(2). All protective elements, links and CT terminals are in correct position and are set to


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correct values and all secondary miniature busbar should be connected.

(3). Trip links can be connected only when voltage across measuring links is zero.

If any of the following abnormal conditions which may cause protection malfunction is found during operation, immediately report to shift supervisors or dispatchers. In case of emergencies, it is allowed to firstly deactivate the protection and then report to shift supervisors and inform relaying protection personnel.

(1) A relay smokes or catches fire.

(2) A relay protective element malfunctions.

(3) A signal which may cause malfunction, such as 1YH broken wire in generator voltage circuits and broken wire in differential circuits, appears.

(4) Other conditions which may cause malfunction.

Operators should accurately record and immediately report operation signals of relaying protections to dispatchers or shift supervisors.

2 Patrol Inspection on Protections and Automatic Devices The protections and automatic devises are correctly started and stopped in accordance with the operating modes of primary equipments.

The status LED, test LED and signal LED of the protections should conform to actual operating conditions and the protective modules in various levels have not malfunction signals.

Power switches of microprocessor-based protections are in normal positions and standby power switches are in standby state.

The terminals of secondary circuits are secure and free from looseness or overheating.

Relay covers are in good order and free of crack; glass covers are free of moisture and have an intact lead seal.

The relay cores are in order, relay contacts are in correct position and free of jittering, burning or blackout.

Relay coils are free of overheating, discoloration, smell, abnormal noises and smoke.

The relay interiors are free of abnormal noises, contacts are free of jittering and coils are free of overheating.

Links, changeover switches, blade switches, fuses, test elements and test terminals are in correct position and securely fixed.

Signal relays don't malfunction.

3 Generator –Transformer Unit Protection 3.1 Brief introduction

The generator-transformer unit protections consist of 2 sets of RCS-985A generator transformer protections and 1 set of RCS-974A transformer non-electrical and auxiliary protection, manufactured by Nari-Relays Electric Co., Ltd. Each set of protection have three panels and all protective components are mounted inside three cabinets. It can provide main protection, protection against abnormal operation and backup protection in redundant mode. Operational circuits and non-electrical protections are mounted inside a separate panel. Two sets of RCS-985A receive signals from different groups of TA, main protection and backup protection share one group of TA and outputs correspond to different tripping coils. The protections have the following benefits:

(1). Simple structure and secondary circuit design;

(2). Easy operation, high safety and reliability and meeting countermeasure requirements;

(3). Convenient setting, commissioning and maintenance.


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3.2 Protective Functions of RCS-985A

◆ Generator protection

Longitudinal differential protection

Power frequency change differential protection

Split-phase transverse differential protection

High-sensitivity transverse differential protection

Longitudinal zero-sequence interturn protection of voltage type

Power-frequency variable directional interturn protection

◆ Generator stator single-phase earth failure protection

Foundational wave zero sequence voltage protection for generator stator earth failure

Third harmonic voltage protection for generator stator earth failure

◆ Generator excitation circuit earth failure protection

Generator rotor single-point earth failure protection

Generator rotor two-point earth failure protection

◆ Generator stator short circuit backup protection

Generator phase-to-phase impedance protection

Composite-voltage overcurrent protection

Generator terminal large-current blocking function (output contact)

◆ Generator protection against abnormal operation

Generator loss-of-excitation protection

Generator loss-of-synchronism protection

Generator reverse power protection

Generator sequential tripping and reverse power protection

Under-frequency protection

Over-frequency protection

Generator over-excitation protection (definite time lag and reverse time lag)

Generator over-voltage protection

Definite and inverse time stator overload protection

Definite and inverse time rotor negative-sequence overload protection

Definite time over-excitation protection

Inverse time over-excitation protection

Inadvertent energizing protection

Generator starting/shutdown protection

Generator shaft current protection

Generator shaft voltage protection

Generator loss-of-voltage protection

Incomplete-phase operation

Balance-of-voltage function


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Broken TA and TV wire judgment

◆ Main MT protection

Differential generator transformer protection

Differential MT protection

Differential MT power frequency change protection

◆ Abnormal operation and backup protection for MT

Impedance protection for MT’s HV side

Composite-voltage overcurrent protection for MT’s HV side

Zero-sequence overcurrent protection for MT’s HV side

Zero-sequence directional overcurrent protection for MT’s HV side

Zero-sequence overvoltage protection for MT’s HV side gap

Zero-sequence overcurrent protection for MT’s HV side gap

Zero-sequence earth alarm for MT's LV side

Definite and inverse time over-excitation protection for MT

MT overload signal

MT cooling fan starting

Broken TV wire

Broken TA wire

◆ HV auxiliary transformer protection

Differential HV auxiliary transformer protection

Composite-voltage overcurrent protection for HV auxiliary transformer

Composite-voltage overcurrent protection for Branch A

Composite-voltage overcurrent protection for Branch B

Zero-sequence overcurrent protection for Branch A

Zero-sequence overcurrent protection for Branch B

Zero-sequence voltage alarm for Branch A

Zero-sequence voltage alarm for Branch B

Auxiliary transformer overload signal

Cooling fan start

Overcurrent output

Broken TV wire

Broken TA wire

◆ Excitation transformer protection

Differential protection

Overcurrent protection

Overload protection (definite time lag and reverse time lag)

Broken TA wire judgment

◆ Other protective functions (RCS-974A transformer non-electrical and auxiliary protection)


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Circuit-breaker pickup failure protection

Incomplete-phase protection for circuit-breakers

◆ Non-electrical protection (RCS-974A transformer non-electrical and auxiliary protection)

Transformers, heavy and light gas of on-load tap changer, pressure relief, oil level& temperature, temperature and coolers totally stopped

Protection for I& C, water failure and excitation system failures

Over-frequency generator tripping

◆ Communication and auxiliary functions

Communication functions (The device has 4 RS-485 ports, 2 multiple optical ports, 1 service port, IEC870-5-103 communication protocol, LFP communication protocol, MODUS communication protocol, via which the device can be connected to DCS systems).

CPU boards: protective and recording functions, MON board: 4s (or 8s) continuous recording function. Data is compatible with COMTRADE format and is not missed during power failure

Windows-based operation management systems are provided and the protection may be directly connected with MIS systems.

3.3 Generator –transformer Unit Protection Configuration

3.3.1 Electrical protection configuration

Main protection: Longitudinal differential protection for generators, generator interturn (Longitudinal zero-sequence voltage or transverse differential protection), MT longitudinal differential, generator-transformer unit differential and HV auxiliary transformer differential protection.

Generator backup protection and protection against abnormal operation: symmetrical overload (reverse time), unsymmetrical overload (reverse time), composite voltage overcurrent, sequential tripping and reverse power, overvoltage, loss-of-excitation, loss-of-step, 100% station earth, over-excitation (reverse time), startup& shutdown, single-point rotor earth, two-point earth , excitation circuit overload (reverse time), low frequency protection, broken TA and TV protection. ,

MT backup protection and protection against abnormal operation: MT impedance, zero-sequence current, overload, fan starting, broken TA and TV wire protection.

Backup ion transformer protection and protection against abnormal operation: composite-voltage overcurrent, delayed rapid breaking and composite-voltage overcurrent protection for Branch A and B, zero-sequence overcurrent, overload and fan starting protection for Branch A and B

Excitation transformer protection: differential protection and overcurrent protection etc.

Other protections: Startup failure protection and non-all-phase operation protection.

Electrical protections are in dual configuration and each set has identical configuration and composed of two layers of fully independent RCS-985A housings. The redundant main protective circuits of the same components are independent from each other, and the redundant protective circuits of the same components are independent from each other. Each set of protection can operate separately for a long time.

3.3.2 Non-electrical protection

It is housed in a separate cabinet and its output is fully independent from the ones for electrical protection. The main functions are as follows:

MT gas protection, temperature, winding temperature, pressure relief, cooler stop and oil level etc.

HV auxiliary transformer gas protection, temperature, pressure relief, cooler stop and oil level etc.


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Non-electrical contacts at transient outputs, such as gas, directly actuate the output relays and CPU software can issue signals and mange printing.

Non-electrical parameters which need be delayed is sent and signaled by CPU software.

3.3.3 Description of RCS-985A protection operation

a) Normal operating state

Indicating lamps are described below:

Green RUN lamp: it turns on when the protection is in normal operation, and turns off when the protection is out of service.

Yellow “TV BROKEN” lamp: it turns on when the TV failures or is broken;

Yellow “TA BROKEN” lamp: it turns on when the TA failures or is broken or differential current is abnormal;

Yellow ALARM lamp: it turns on when the protection generates an alarm;

Red TRIP lamp: it turns on when the protection is triggered. It turns off when the protection drop out and the RESET button is pressed or a remote reset signal is received.

b) Operating conditions and description

(1) The protective output may be enabled or disabled by means of output trip links.

(2) A protective function may be separately enabled or disabled through panel-mounted links, internal links and control words.

(3) The protection always detects hardware circuits and operating status. In case self test failure, inform relaying protection personnel. In case of a fatal failure (notes; indicated with a * symbol), the protection will block all functions and the RUN lamp will turn off. Otherwise, some protective functions will be ineffective and an alarm signal will be issued.

(4) For cooling fan starting and voltage regulation blocking, the protections will send a message other than an alarm signal (notes; indicated with a # symbol).

c) Protection blocking and alarm

(1) When the CPU detects a hardware failure, the entire protection will be blocked. Hardware failures include RAM failure, program memory error, EEPROM error, invalid set value, optoelectronic isolator loss-of-voltage alarm, DSP error and trip output failure etc. In this case, the protection can not continue to operate.

(2) When the CPU detects a long starting time, unacceptable starting, internal communication error, broken TA, broken TV and alarm signals, the protection will issue an alarm signal. In this case, the protection can continue to operate.

3.3.4 Description of RCS-974A protection operation

a) Normal operating state

Indicating lamps are described below: The green RUN lamp turns on when the protection is in normal operation, and turns off when the protection is out of service. The yellow ALARM lamp turns on when the protection detects a failure. The red “ELECTRIC TRIP” lamp turns on when the non-all-phase protection is triggered and output; The red “NON-ELECTRICAL DEALYED TRIP” lamp turns on when the delayed non-electrical protection is triggered and output. The “1, 2, 3……

16” lamps turn on when the external non-electrical signal contacts are closed. The protection “ALARM” lamp will automatically turn off when a failure is cleared. The “ELECTRIC TRIP”, “DELAYED NON-ELECTRICAL TRIP” and “1, 2, 3…16” lamps turn off only when the “signal reset” button is pressed or remote reset signal is received.

b) Operating conditions and description


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(1) The protective output may be enabled or disabled by means of output trip links.

(2) A protective function may be separately enabled or disabled through panel-mounted hard links or control words.

(3) The protection always detects hardware circuits and operating status. In case of a fatal failure (notes; indicated with a * symbol), the protection will block all protective functions and the RUN lamp will turn off. If other failures occur, only some protective functions will be disabled.

c) Protection blocking and alarm

(1) When CPU detects a hardware failure, the entire protection will be blocked. Hardware failures include memory failure, program area error, illegal set value, optoelectronic isolator loss-of-voltage alarm, DSP error, CPU sampling failure and trip output failure etc. In this case, the protection can not continue to operate.

(2) When the CPU detects a long starting time, failure TA, start failure, the protection will issue an alarm signal. In this case, the protection can continue to operate.

3.3.5 Provisions on turning on or off protective links

Due to interference between two sets of rotor earth failure protections, only one set is enabled. When a protection need be disabled, another set of rotator earth failure protection should be enabled.

The links for startup& shutdown and power-on error protection should be set to ON when the generator transformer unit is disconnected from power grids, and be set to OFF when the generator transformer unit is connected with power grids.

After the generator transformer unit is disconnected from power grids, the output links used to trip the relevant circuit-breakers on non-electrical protective panels should be set to OFF

4 Microprocessor-based Generator Synchronizer WX-98F/8 synchronizer is an automatically microprocessor-based one used for synchronization between power generating sets and power grids and between substation busbar and lines. It is characterized by high safety, high reliability, fast response, high accuracy and multiple functions. Meanwhile, during synchronization, the synchronizer can protect against and generate an alarm for high or low system voltage, high or low system frequency, high or low unit voltage, high or low unit frequency, broken voltage circuit wire and over-excitation, etc.

4.1 Main Functions of Synchronizer

Broken wire blocking for voltage circuit and undervoltage blocking

If a wire in voltage circuit is broken or synchronizing voltage is lower than the set value during synchronization, the device will refuse synchronization, generate an alarm and indicate that the generator voltage or system voltage is too low.

Overvoltage and over-excitation protection

A high generator voltage may cause over-excitation of the generators (including transformers in case of the generator transformer set). The device can protect generators against over-voltage and over-excitation. When the generator voltage exceeds the preset value, the device will refuse synchronization and generate an alarm. The over-voltage can be preset.

Overfrequency or underfrequency protection

In order to ensure that the generator is connected with power grids safely, the device is provided with overfrequency or underfrequency protective abilities. When the preset frequency value is exceeded, the device will refuse synchronization and generate an alarm. The high and low frequency threshold may be preset for systems and generators, respectively.

The device supports line voltage synchronization and phase voltage synchronization.


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The device is able to automatically compensate phase angle and voltage difference caused by MT's delta or Y-connection without the need for a corner transformer.

The device is able to measure the closing time of synchronized circuit-breakers in real-time way.

A commissioning module which can generating synchronizing voltage having adjustable frequency and amplitude (phase) is built in the device for the use for tests.

The device can be flexibly started up.

Manual startup, automatic startup, single-shot starting and multiple-shot startup may be accomplished by varying input terminal wiring combination to facilitate the coordination with manual control, DCS system and ECS systems.

Control signals and object selection signals may be either long pulse ones or short pulse ones depending on users’ selection.

The device has SYNCHRONIZATION IN PROGRESS output contacts and a RESET contact used to cancel synchronization in case of emergencies.

The device has communication ports.

The device has 2 RS-485 ports. One port (A1, B1) transmits device operation and alarm information via MODBUS communication protocol. A waveform diagram may also be sent when necessary. Synchronization meters and real-time information may be displayed on a PC via another port (A2 and B2, which may be RS-232).

The device can greatly simplify multi-objective synchronization wiring together with YAC-2000 smart control boxes and GR-3C smart control boxes.

Voltage-free synchronization may be performed when necessary.

Chinese MMI

Easy operation, commissioning and maintenance

The device may be time synchronized to 1 s through GPS.

4.2 Entire Operation Process of Synchronizers

The DCS chooses and maintain a synchronizing point.

In order to ensure that the synchronizers perform SYNCHRONIZATION METER, SINGLE-SIDE VOLTAGE-FREE closing and DOUBLE-SIDE VOLTAGE-FREE closing, the DCS will set and maintain the relevant digital input. This step will be skipped for synchronization operation.

The synchronizer is turned on and its contact is a short signal;

The DCS starts up the synchronizer and its contact is a short signal;

The synchronizer is started up and cause circuit-breakers to be closed;

The synchronizer is turned off under the control of the DCS and its contact is a short signal;

The DCS reset the SYNCHRONIZATION POINT SELECTION, SINGLE-SIDE LOSS OF VOTLAGE confirmation and DOUBLE-SIDE LOSS OF VOTLAGE confirmation signals;

If the DCS selects the SYNCHRONIZATION METER in the second step, the synchronizer is mainly used as a synchronization meter and real-time parameters such as voltage and frequency may be displayed on screens. If AUTOMATIC FREQUENCY REGULATION and AUTOMATIC VOLTAGE REGULATION parameters are chosen, the frequency and voltage may be controlled; hut closing control will not be performed.

5 150kV Circuit-breaker Protection 5.1 150kV Circuit-breaker Protective Functions

One protective panel is provided for each 150kV circuit-breaker and contains failure protection,


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three-phase discrepancy protection, recloser, dead zone protection, charging protection and phase-splitting control box. Circuit-breakers only associated with transformers have not reclosing ability. There are isolators in 3 sets of generator transformer sets, startup/ backup transformer’s HV side and 4 outgoing lines. Redundant stub protection is provided.

5.2 Technical Requirements for Automatic Reclosing

One-shot automatic reclosing mode is adopted and many-shot reclosing is forbidden in any case.

Reclosing starting mode

a） Automatic reclosing is triggered by line protection tripping contacts from tripped positions.

b） Automatic reclosing is triggered phase-splitting and three-phase tripping circuits. Three-phase reclosing should be subjected to synchronization check and voltage check.

c） After receiving starting pulse, the recloser can hold the starting signal for a preset time.

Reclosing block mode

Reclosers should have input circuits used to block reclosing. The input is connected to reclosing block contacts in case of manual tripping, manual closing, busbar failure, transformer failures, circuit-breaker failure, circuit-breaker three-phase discrepancy, remote tripping, delayed protection and drop in circuit-breaker operating pressure. After the three-phase reclosing elements are actuated, the single-phase reclosing time elements should be blocked.

This reclosing is used for 1 1 circuit-breakers and therefore each line has two circuit-breakers. The circuit-breaker will be firstly closed when the FIRST RECLOSER ON links are closed. A single-shot closing pulse (pulse time: 120ms) will be sent after a short delay time (preset for reclosing). When the first recloser picks up, a CLOSING RECLOSER signal will be sent. If the first recloser drops out and a reclosing pulse is not sent, the FIRST RECLOSER BLOCKED contact will instantaneously drops out. If the first recloser has sent a reclosing pulse, the contact will drop out only after the device begins to drop out. When first reclosing is used together with subsequent reclosing, the FIRST RECLOSER BLOCKED output contacts of the first recloser will be connected to the FIRST RECLOSER BLOCKED input contacts of the subsequent recloser.

The circuit-breaker will be subsequently re-closed when the FIRSTLY CLOSING ON links are opened The reclosing pulse is sent after a long delay time (set re-closing time +subsequent reclosing delay time). When the first recloser is maintained or out of service, it will not send a FIRST RECLOSER BLOCKED signal. In this case, the subsequent recloser will pick up after the preset reclosing delay time to eliminate unnecessary delay time and ensure system stability.

Reclosing modes

There are the following several reclosing modes: 1. adaptive reclosing mode; 2. Ordinary reclosing mode; 3. reclosing shutdown mode. For simple operation, the ADAPTIVE RECLOSING ON in the protection for #1 and #2 line and the RECLOSING ON and ADAPTIVE RECLOSING ON in RSC921-A should set to 1. The protective links for tripping starting circuit-breakers, closing starting circuit-breaker protection and the protection block circuit-breaker reclosing on #1 and #2 protective panels should be ON. The reclosing mode changeover switch on #1 and #2 protective panels should be in OFF position. The FIRST RECLOSING LINK on ? ? circuit-breaker protective panel should be ON. The FIRST RECLOSING LINK on ? ? circuit-breaker protective panel should be OFF. Reclosing modes are changed over by means of the following changeover switches and hard links.


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Reclosing modes Circuit-breaker protective panel Protective panel

for #1 line Protective panel for #2 line

“Reclosing mode switch”

“Adaptive reclosing link ON”

Reclosing output link

Link of “three-phase trip through communication line”

Link of “three-phase trip through communication line”

Adaptive reclosing ON

Single-shot reclosing ON ON OFF OFF

Common reclosing ON

Single-shot reclosing OFF ON OFF OFF

Reclosing OFF Out of service OFF OFF ON ON For manual closing or reclosing of intermediate circuit-breakers, only the protection of energized lines or lines which failure previously should be accelerated. It is not allowed to accelerate the protection of nearby good lines.

The reclosing pulse should be wide enough (120ms) to ensure reliable closing and prevent secondary reclosing or bouncing.

Re-closing time

a） The single-phase reclosing time and three-phase reclosing time may be adjusted respectively. The time may be adjustable between 0.3s and 9.9s in a step of 0.1s (or lower).

b） After reclosing pickup, the resetting time of entire groups is adjustable between 1 and 99s. During the time, signals which will be sent to the protection for three-phase trip should be held.

In case any component of a recloser is damaged or failure, multiple-shot reclosing and three-phase reclosing forbidden should not occur. Two-shot reclosing should not occur in any case.

When a recloser is being reset, out of service, blocked or failures, triple tripping circuit of the circuit-breaker should be connected.

A recloser has a circuit which blocks reclosing in case of low circuit-breaker operating pressure The circuit only ensure that the operating pressure is appropriable before circuit-breaker tripping.

A recloser should provide adequate output contacts to accelerate delayed protection.

A recloser should provide the protection with sufficient, independent output contacts so as to protect three-phase trip in case of the following conditions:

a） Reclosing on failure lines

b） When the reclosing selective switch is in RECLOSING OFF position or THREE-PHASE RECLOSING position.

c） A recloser failures

There are sufficient amount of signal circuit contact output:

a） There are three pairs of independent reclosing actuation signal output contacts, which are used for startup central signals, even recorders and remote signals.

b） When a recloser is out of service, there are one pair of independent signal output contact for starting central signals

c） Recloser failure signal

d） After the loss of DC power, there are signal output contacts for the use by central signals.

Three-phase trip through communication line


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a） After two phases are tripped due to a transferable failure (failures transferable from Phase A to B) in protected lines or other reasons, it is necessary to trip the third phase as soon as possible.

b） When a single-phase failure occurs in the protected lines and it is necessary to trip three phases due to automatic reclosing (for example, reclosing is not allowable due to reduced operating gas (hydraulic) pressure), the circuit-breakers must be three-phase tripped.

c） For circuit used for three-phase trip through communication line of reclosers, the reclosers constitute tripping logic and the line protection does not provide output trip contacts for three-phase trip through communication line.

5.3 Circuit-breaker Failure Protection

Circuit-breaker failure protection should take account of failure phase failure, non-failure phase failure and generator-transformer three-phase trip failure. In addition, the failure protection will also be triggered when the energization protection is active.

Failure phase failure: After the line protection trip contacts and high failure overcurrent setpoint are actuated, a three-phase tripping command is sent after a “Failure Tripping Delay Time” to trip the circuit-breaker and then the nearby circuit-breakers are tripped after a “Failure Actuation Time”.

Non-failure phase failure: The three-phase tripping input contact hold high failed overcurrent setpoint elements and the low failed overcurrent setpoint elements operate continuously. In this case, the output actuation logics firstly send three-phase tripping commands to trip the circuit-breaker after a “Failure Tripping Delay Time” and then trip the nearby circuit-breakers after a “Failure Actuation Time”.

Generator-transformer three-phase trip failure: The generator-transformer three-phase trip failure protection may be triggered by three criteria, namely, low power factor, negative-sequence overcurrent and zero-sequence overcurrent. The three auxiliary criteria may be ON or OFF through a setting control word. In this case, the output actuation logics firstly send three-phase tripping commands to trip the circuit-breaker after a “Failure Tripping Delay Time” and then trip the nearby circuit-breakers after a “Failure Actuation Time”.

Energization protection starting failure: If the failure protection is ON when the energization protection is triggered, the nearby circuit-breakers are tripped after a “Failure Actuation Time”.

5.4 Three-phase Discrepancy

When the discrepancy protection is ON, the TWJ of any phase is actuated and the current is zero, the contacts of this phase are deemed to be in tripped position. If any pole is in tripped position and the remaining two phases are not in tripped position, three phases are considered as discrepant. The discrepancy protection may be open to zero-sequence current or negative-sequence current and enabled or disabled by control words. When the settable actuation time meet the discrepancy actuation conditions, its output will trip the circuit-breaker.

5.5 RCS-922A Stub Protection

RCS922-A digital stub protective devise is mainly used for stub protection. It may also be used for line energization protection. RCS922—A adopts differential current ratio mode. The differential ratio protection is enabled when the auxiliary contacts of line blade switches or the ones of the output blade switches on MT HV side are closed or the protective links on panels are ON, and the differential protection control word is set to 1. The starting elements of the devices is accomplished by overcurrent relays reflecting the change in frequency and supplemented by zero-sequence overcurrent relays reflecting full current. The line energization protection is composed of 2 sections of overcurrent protection The setting control word control is enabled through panel-mounted protective links, line isolating switches and energization protection.

RCS-924A Zone T protective device is mainly used to protect Zone T connected in 1 1mode. The


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device is composed of differential current protection of three-side and line energization protection. When the line isolator is opened, the differential current protection of three-side will be automatically changed to differential current protection of two-side and two-section overcurrent protection on line side will be open.

5.6 Circuit-breaker Operator Box

An operational box for circuit-breakers is device for use with circuit-breakers having 2 split-phase tripping coils and 1 closing coil. When the protection is triggered or circuit-breakers are manually operated, the operational relay box can trip, close and reclose circuit-breakers.

The operational relay box has split-phase tripping circuits, three-phase tripping circuits, permanent tripping (not reclosing) circuits, manual tripping circuits and tripping holding circuits.

The operational relay box has reclosing circuits, manual closing circuits and anti-bouncing circuit for manual closing on permanent failures.

It has a reclosing pressure and tripping pressure monitor circuit to prevent damage to circuit-breakers due to abnormal operating gas (hydraulic) pressure.

It has closing position relays and tripping position relays

It has protection acceleration or blocking circuits, reclosing starting and blocking circuits and circuits to HF protections.

It should have necessary signal outputs: tripping signal, low circuit-breaker gas (hydraulic) pressure signal, loss-of-DC current of tripping and closing circuits, broken control wire signal, circuit-breaker position signal and remote signals.

In order to ensure that reclosing and failure protection are not triggered due to tripped output of non-electrical generator transformer protection, the two tripping coil operational circuits of three circuit-breaker protective cabinets associated with MT have circuits connected with non-electrical MT protection. It is started by the tripping contacts of non-electrical MT protections and the circuits are connected to tripping circuits of Phase A, B and C.

6 150kV Line Protection The 150kV line protection consists of one set of RCS-902A digital rapid ultra-HV line protective device and one set of RCS-9611C line protection and measurement device.

6.1 RCS-902A Digital Rapid Ultra HV Line Protective Device (for 150kV Line)

6.1.1 Device Function

RCS-902A consists of a main protection and quick section I protection. The main protection is based on longitudinal distance element and zero-sequence distance elements and the quick section I protection is composed of power frequency variation distance elements. RCS-902A has a complete backup protection consisting of three-section phase-to-phase protection, earth distance protection and two zero-sequence directional overcurrent protection. RCS-902A protection has split outputs and auto-reclosers which perform single-phase reclosing, three-phase reclosing and general reclosing of circuit-breakers connected with single or double busbar.

6.1.2 Performance Characteristics

Rapid response. The circuit-breakers are tripped within 10ms after a nearby line failure occurs and within 15ms when an intermediate line failure occurs. The circuit-breakers are tripped within 25ms after a remote line failure occurs. The main protection adopts fast integral algorithm and the backup protection adopts accurate Fourier algorithm. The power frequency change measuring elements adopts adaptive floating threshold to protect against system imbalance and interference. Therefore, the measuring elements are safe and has fast response capability and the pickup is very sensitive and frequent actuation can be avoided. The advanced oscillation block feature ensures that the distance protection can be suitably blocked in case of failures beyond additional system oscillation zones, and clear a failure occurring within additional oscillation zones. The device has auto-reclosing


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modes. The device has an integral panel and totally-enclosed housing, traditional wiring at back planes is eliminated. The software design also takes account of interference suppression and electromagnetic radiation complies with the standards. The device can suitably process even messages and store the latest 128 action events and 24 failure records. The device has a friendly and Chinese MMI and print reports in Chinese. It is provided with flexible background communication modes and RS-485 communication ports (optional twisted pairs, optical fiber cable) or Ethernet. It is compatible with DL/T667-1999 (IEC60870-5-103) communication protocol. Its disturbance recorder is compatible with COMTRADE.

6.2 SRCS-9611C Line measuring and Protective Device

6.2.1 Configuration and functions of protection

a) Protection configurations

1） Three-section overcurrent protection which can be composite voltage and direction blocked.

2） Three-section zero-sequence overcurrent protection

3） Fast overcurrent protection and fast zero-sequence protection (zero-sequence current may be generated by the protection or externally applied)

4） Overload function (alarm or tripping)

5） Load reduction in case of low frequency

6） Three-phase single-shot reclosing

7） Low current grounding line selection device (zero-sequence current must be externally applied)

8） Independent operating circuit.

b) Measuring and control functions

1）Customized 20-way digital input for remote signaling.

2） One group of circuit-breakers are remotely closed or opened (up to three groups are optional)

3） Iam、Icm、I0、UA、UB、UC、UAB、UBC、UCA、U0、F、P、Q、COS 14 parameters including Iam, Icm, I0, UA, UB, UC, UAB, UBC, UCA, U0, F, P, Q, COSф can be remotely measured.

4）SOE record, etc

c) Protection information functions

1）Remotely viewing device description

2） Remotely viewing system setpoint

3） Remotely viewing and modifying setpoint and zone Nr.

4） Remotely viewing, enabling, disabling and controlling soft links.

5）Remotely viewing digital inputs of the protection

6） Remotely viewing device operating status (including protective element actuation, alarm and self-test information).

7） Remotely resetting device signals

8） Uploading recorded failures.

The protection conforms to DL/T667-1999 (IEC60870-5-103) communication protocols and


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equipped with Ethernet communication (100Mbps) and Category 5e cables or optical communication ports.

6.2.2 Performance characteristics

Complete protective functions, fast response and reliable performance

Diversified operating circuit configuration which can adapt with various operating mechanisms.

Powerful optional modules which meet various field demand

The device has a totally-enclosed housing, electrical circuits are separate from electronic circuits, the traditional wiring at back planes is eliminated. The software design also takes account of interference suppression and electromagnetic radiation complies with the standards.

The device has complete event reporting and processing functions and is able to store the latest 64 action events, the 256 latest SOE events, 64 latest user action events and up to 8 failure events (the failure recording time is up to 15s).

Friendly MMI and Chinese display and report.

Flexible background communication modes, Ethernet communication ports (Optional Category 5 cable or optical cable)

Several separate Ethernet ports (two or three ports are provided and specified at the time of order)

Independent and reliable channels, which supports communication among station-wide supervisory control background and protect information workstation and dispatching centers).

6.2.3 Operation description

a) Indicating lamps

Green RUN lamp: it turns on during normal operation

Yellow ALARM lamp: it turns on when an alarm is generated;

Red TRIP lamp: it turns on when the protection is tripped and turns off when the signal is reset.

Red CLOSING lamp: it turns on when the circuit-breaker is closed and turns off when the signal is reset.

Green TRIPPED lamp: it turns on when the circuit-breaker is in open position.

Red CLOSED lamp: it turns on when the circuit-breaker is in the closed position.

b) Device operation description

Normal operating state

The RUN lamp should remain On and the ALARM lamp (yellow) should remain Off when the device is in normal operation.

Press the ACK button on the main menu to reset all TRIPPED or CLOSED lamp and return the LCD display to the normal screen.

7. 150kV System Busbar Protection The 150kV system busbar protection is RCS-915E microprocessor-based busbar protection manufactured by Nari-Relays Electric Co., Ltd. It is mainly suitable for one and a half circuit-breaker connection mode. Up to 9 lines and elements may be connected with the busbar. Each busbar are provided with two sets of RCS-915E microprocessor-based busbar protection.

7.1 Protection Configurations

RCS-915E microprocessor-based busbar protection is composed of differential busbar protection and circuit-breaker failure protection.

7.2 Performance Characteristics


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1） A different TA ratio is allowable and the TA adjustment factor is settable.

2） High-sensitivity differential ratio protection

3） New adaptive weighed criteria for TA saturation resistance

4） Integral event message processing

5） Flexible background communication, RS-485 and optical fiber communication ports (optional)

6） COMTRADE-compliant disturbance recorders

7.3 Differential Busbar Protection

It is composed of split-phase ratio differential elements.

1） Pickup elements:

The pickup element for split-phase ratio differential protection is composed of power frequency current change elements and differential current elements. When the change in braking current is greater than the threshold (consisting of a floating threshold and fixed threshold), the power frequency current change elements will operate. When the differential current of any phase is greater than the threshold, the differential current elements will operate.

2） Ratio differential elements

3） Ratio differential elements

Composed of common ratio differential elements and percentage power frequency change differential elements.

7.4 Circuit-breaker Failure Protection

It works with the failure protection for one and a half circuit-breaker to accomplish interlocked tripping function. When certain circuit-breaker connected with busbar fails, a failure protection actuation contact for the circuit-breaker is sent to this device. When the digital failure input contact picks up and the protection detect its operation, all components connected to the busbar will be tripped as an interlock mean.

7.5 Check for Broken AC Current Circuits

1） When the large differential current is greater than the set value for broken TA wire (IDX), an alarm will be generated to indicate TA wire breakage after a delay time of 5s.

2） Determine whether differential busbar protections are blocked after a broken TA is detected, by setting the control word ”Blocking Differential Protection after TA Breakage”. If the control word is set, the differential busbar protection will be blocked when a TA wire is broken (other protection will not be blocked). The differential busbar protection can not restore normal operation until operators press the RESET button on a panel to reset alarms.

3） In case of 3I0>0.25Iфmax+0.04In in any branch, an alarm will be generated to indicate TA failure after a delay time of 5s. This feature may be disabled by resetting the control word “TA Abnormal Imbalance Criteria ON”

4） When the large differential current is greater than the TA alarm value (IDXBJ), an alarm will be generated to indicate TA failure after a delay time of 5s.

5） When a TA failure alarm is active, the differential busbar protection will not be blocked. Determine whether a TA failure alarm is automatically reset after the circuit becomes normal, by using the control word “Automatic Recovery after TA Failure” during busbar protection setting.

7.6 Device Operation Description

7.6.1 Device Composition


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The device is housed a 8U standard totally-enclosed housing and composed of digital input circuits, output and signal circuits, power source modules, CPU boards, plug-in manager board and AC input circuits.

A 9-key keypad and 4 lamps are mounted on the device panel.

Indicating lamps are described below:

Green RUN lamp, it turns on during normal operation

Red DIFFERENTIAL BUSBAR PROTECTION lamp: it turns on when the differential busbar protection trip the busbar circuit-breakers.

Red FAILURE PROTECTION lamp: it turns on when the circuit-breaker failure protection is active.

Yellow BROKEN WIRE ALARM lamp: it turns on when AC circuits failure.

Yellow ALARM lamp: it turns on when other failures occur;

There are two pushbuttons at the right upper part of front panel. They are the signal reset button and print button.

The RESET button is used to reset the protection and the PRINT button is used to print failure reports. Links, including protection ON links and links at output to various connected components, are arranged at the lower part of the cabinet. A DC air switch is mounted at the top of cabinet rear panel.

7.6.2 Failure Information and Recommended Treatment

Self-test Information

Meaning Remedial Method

Protective board (manager board) Memory error

The protective board (manger board) RAM chip is damaged, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.

Immediately shut down the protection and notify the manufacturer.

Protective board (manager board) Program error

The protective board (manger board) FLASH content is corrupted, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.

Protective board (manager board)

Setpoint error

The set value area of the protective board (manger board) is corrupted, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.


DSP setpoint error

The checksum error of DSP set value area of the protective board (manger board) occurs, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.


FPGA error

The checksum error of the FPGA chip on the protective board (manger board) is detected, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.


CPLD error

The checksum error of the CPLD chip on the protective board (manger board) is detected, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.


DSP error

The DSP self testing of the protective board (manger board) failed, the FPGA is reset, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.

Trip output alarm An output transistor is damaged, the DEVICE BLOCKING and OTHER ALARM signals are


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issued and the protection is blocked. Sampling check error

The digital input of the protective board and manager board is not consistent, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.

Manager boards generate digital

output alarm

When the protective board is not triggered, the manger board is triggered for a long time and generates OTHER ALARM signal, the protection is not blocked.


Invalid setpoint in areas

Set values in the area are invalid, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.

After the set value area number or system parameter setpoint is set, the set values for differential busbar protection and failure protection must be re-set.

Self-test Information Meaning Remedial Method

Protective board (manager board) Memory error

The protective board (manger board) RAM chip is damaged, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.


Protective board (manager board) Program error

The protective board (manger board) FLASH content is corrupted, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.


Setpoint error

The set value area of the protective board (manger board) is corrupted, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.


DSP setpoint error

The checksum error of DSP set value area of the protective board (manger board) occurs, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.


FPGA error

The checksum error of the FPGA chip on the protective board (manger board) is detected, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.


CPLD error

The checksum error of the CPLD chip on the protective board (manger board) is detected, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.


DSP error

The DSP self testing of the protective board (manger board) failed, the FPGA is reset, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.

Trip output alarm An output transistor is damaged, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.

Sampling check error

The digital input of the protective board and manager board is not consistent, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.

Manager boards generate digital

When the protective board is not triggered, the manger board is triggered for a long time and

Immediately shut down the protection and notify


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output alarm generates OTHER ALARM signal, the protection is not blocked.

the manufacturer.

Invalid setpoint in areas

Set values in the area are invalid, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is blocked.

After the set value area number or system parameter setpoint is set, the set values for differential busbar protection and failure protection must be re-set.

Optocoupler loss of power The 24V positive power source of optocouplers

fails, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is not blocked.

Check that optocoupler power source of power source boards and isolated power source of digital I/O boards are correctly wired.

Internal communication error The communication between the protective board

and manger board fails, the OTHER ALARM signals are issued and the protection is not blocked.

Check that the communication cable is correctly connected between the protective board and manager board.

Protective board (manager board) is triggered for a long

time 1

The DSP1 pickup elements of the protective boards (manger boards) are triggered for a long time (differential busbar protection is triggered for a long time), the OTHER ALARM signals are issued and the protection is not blocked

Check secondary circuits for wiring (including TA polarity)

Protective board (manager board) is triggered for a long

time 2

The DSP2 pickup elements of the protective boards (manager boards) are triggered for a long time (the failure protection is triggered for a long time), the OTHER ALARM signals are issued and the failure protection is blocked

Check secondary circuits for wiring (including TA polarity) and failure contacts

Broken TA wire The CT secondary circuit is broken, a BROKEN WIRE alarm is generated and the differential busbar protection is blocked or not blocked depending on the setting.

Immediately shut down the protection and check TA secondary circuits .

TA failure CT secondary circuits fails, a TA FAILURE alarm is generated and the differential busbar protection is not blocked.

Check the TA’s secondary circuits.

Panel communication error

The communication between the panel CPU and protective board's CPU fails, the OTHER ALARM signals are issued and the protection is not blocked.

Check that the communication cable is correctly connected between the panel and protective board.

Optocoupler

The 24V positive power source of optocouplers fail, the DEVICE BLOCKING and OTHER ALARM signals are issued and the protection is not blocked.

Check that optocoupler power source of power source boards and isolated power source of digital I/O boards are correctly wired.

Internal communication error The communication between the protective board

and manger board fails, the OTHER ALARM signals are issued and the protection is not blocked.

Check that the communication cable is correctly connected between the protective board and manager board.


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triggered for a long

time 1

The DSP1 pickup elements of the protective boards (manager boards) are triggered for a long time (differential busbar protection is triggered for a long time), the OTHER ALARM signals are issued and the protection is not blocked

Check secondary circuits for wiring (including TA polarity)


triggered for a long time 2

The DSP2 pickup elements of the protective boards (manager boards) are triggered for a long time (the failure protection is triggered for a long time), the OTHER ALARM signals are issued and the failure protection is blocked

Check secondary circuits for wiring (including TA polarity) and failure contacts

Broken TA wire The PT secondary circuit is broken, a BROKEN WIRE alarm is generated and the differential busbar protection is blocked or not blocked depending on the setting.

Immediately shut down the protection and check TA secondary circuits.

TA failure CT secondary circuits fails, a TA FAILURE alarm is generated and the differential busbar protection is not blocked.

Check the TA’s secondary circuits.

Panel communication error

The communication between the panel CPU and protective board's CPU fails, the OTHER ALARM signals are issued and the protection is not blocked.

Check that the communication cable is correctly connected between the panel and protective board.

8. Computer-based Step-up Substation Supervisory Control System 8.1 Functions of Computer-based step-up Substation Supervisory Control System

The 150kV step-up substation supervisory control system adopts NSC3000X system.

8.2 Main Features of NCS300UX Supervisory Control System

The system provides simple three-phase unbalance supervisory control function. The three-phase imbalance in voltage, current and other parameters is often a sign of failure or failures. NSC300UX is able to simplify the control and judgment course.

(1). Eliminating invalid information

(2). Automatic monitoring and recording functions.

(3). Remote control configuration

(4). The system provides many data import and export functions

(5). Alarm window processing

8.3 NSC300UX Architecture

NSC300UX SCADA/EMS architecture may be described in two regards, namely system structure and internal module structure.

8.3.1 System Structure

The NSC300UX SCADA/EMS system is a multi-computer and dual network structure.

The dual network refers to Net A and B, which back up each other. The configuration can prevent system collapse in case of failure of any one network, and avoid excessively heavy load on one network.

The multi-computer system is based on one server and client model. The entire system may have two servers and up to 40 clients. The system may be configured as load sharing or redundant mode. If the system is configured as redundant mode, the system should be defaulted to fixed hot standby mode. However, forced changeover is also allowable.


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8.3.2 Main functions of computer-based supervisory control system:

Real-time data sampling and processing

Alarm processing

SOE record and PDR function

Control function (switch interlocking and AVQC strategy etc)

Online statistical calculation

Menu, table display and printing

Clock synchronization

Information exchange with remote dispatching and control centers

Communication with relaying protections

Communication with other plant-wide IEDS

Self- diagnostic and self recovery

Maintenance functions

Separate dual power switching devices are provided on each I/O measuring and control panel of bay level equipments. When one power source unit fails, disturbance-free changeover to another power source unit will occur. The LOCAL/REMOTE, INTELOCK/UNLOCK changeover switches as well as manual control buttons are provided on the I/O measuring and control device. On one hand, the I/O measuring and control device directly acquires, process and transit field data to station-level computers. On the other hand, the I/O measuring and control device receive the commands from station control level, judge the invalidity, detect block error and synchronization and finally execute the commands.

150kV part: Each 150kV string is divided into three electrical units, that is to say, each circuit-breaker is provided with one NSC681 measuring and control device to perform acquisition, control, operation blocking and time synchronization functions. Three NSC681 of each string constitute one panel. One NSC681 is provided for 150kV line and another NSC681 common measuring and control device is provided.

In addition, one protection and communication manager panel is provided. Disturbance recorder and DC kilowatt hour meter information is sent to the protection and communication manger, which is directly connected with Ethernet

The entire bay level has three panels which are mounted in the network control relay rooms.

9. Startup/backup Transformer Protection The startup/ backup transformer is equipped with 2 RCS-985T and RCS-921A Zone T protections and RCS-974AG2 non-electrical and auxiliary transformer protection. The hardware system of RCS-985T is based on high-performance DSP chips and 32-bit CPU. Therefore, it is a real digital transformer protection.

The RCS-985T transformer protection adopts master/salve solution and is able to perform all electric protection required by a transformer. It is suitable for the protection of transformers, such as multi-branch startup/backup transformers, auxiliary transformers and main transformers.


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9.1 Protective functions of 1RCS-985T

No. Protective functions No. Protective functions 1 Variable slope ratio differential protection (up to

7 sides) 10 Overload alarm

2 Differential instantaneous tripping protection 11 Zero-sequence voltage alarm for branches

3 Composite-voltage overcurrent protection for HV side

12 Cooling fan start

4 HV side zero-sequence (directional) overcurrent protection

13 Voltage regulation blocked

5 Gap overcurrent protection for HV side 14 Three-phase discrepancy alarm 6 Gap overvoltage protection for HV side 15 Broken TV judgment 7 Composite-voltage overcurrent protection for

LV-side branch (up to 6 branches)

16 Broken TA judgment

8 Zero-sequence overcurrent protection for branches

17 Transformer over-excitation protection

9 Incomplete-phase operation 18 Zero-sequence differential protection (HV side, branch limited earth protection)

9.2 Other functions

No. Other functions No. Other functions 1 4 RS-485 communication ports 6 MODBUS communication protocol 2 2 multiplex optical fiber interfaces 7 CPU board: protection and disturbance

recorder function 3 1 commissioning port 8 MON board: 4s (or 8s) continuous

Disturbance recorder function 4 IEC870-5-103 communication protocol 9 Printing: set values, message and

waveform in Chinese 5 LFP communication protocol 10 Display: set values and message

Notes: refer to the line protection for the RCS-924A Zone T protection, and to the generator-transformer unit protection for RCS-974AG2 non-electrical and auxiliary transformer protection.

10 Rapid Auxiliary Power Change-over Device Section 31, 32 and 33A/B of 6kV auxiliary power supply system are provided with three panels and six MFC2000－3A microprocessor-based rapid auxiliary power changeover device manufactured by Wiscom Electrical Co., Ltd. MFC2000－3A adopts 4U housings, 32-bit microprocessors, DSP structure and back plane structure and bus back plates. There is not tie wires. A 320×240 dot matrix color LCD is mounted on the device panel. Therefore, technical performance, reliability and MMI friendliness are greatly improved.

10.1 Main Features of the Device

The device has complete changeover functions, including manual changeover, parallel changeover, simultaneous changeover and tandem changeover. The parallel changeover is further divided into automatic and semi-automatic changeover. The automatic changeover includes emergency changeover and abnormal changeover, tandem changeover and simultaneous changeover. The changeover mode includes rapid changeover, synchronized changeover, residual voltage changeover and delayed changeover, Constant leading time and constant leading phase angle may be chosen for synchronized capturing changeover.

The device is able to operate separately and turn on or off auxiliary power supply systems in


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synchronized or voltage-free way.

It is suitable for cold and hot standby power source modes. It can be used for auxiliary power changeover in which standby power source is in cold or hot standby modes.

10.2 Device Software

MFC2000-3A quick changeover device adopts dual CPU system. The software is composed of two parts which are executed by a master CPU and slave CPU respectively.

Software for master CPU: include digital input detecting, changeover action, output, test, signal and self-testing modules as well as DSP sampling and frequency &phase angle calculation programs.

Slave CPU software: including LCD, printing, communication and GPS time synchronizing modules.

10.3 Main Technical Specification

Environmental conditions

Ambient temperature: -10 to +55℃;

Relative humidity: 5%～90% (non condensing)

Atmospheric pressure: 80～110kPa

DC power supply:

Rated voltage: DC220V/DC110V or AC220V

Allowable variation: -20%～+10%

Ripple coefficient: no more than 5%

Rated AC Input

AC current: 5A

AC voltage: 100V or 57.7V

Frequency: 50Hz

Quick changeover time

(1). Simultaneous emergent changeover: ≦10 ms＋user-set delay time +standby circuit-breaker closing time (to be calculated from the closure of external protective pickup contact to the closure of standby circuit-breaker)

(2). Tandem emergent changeover: ≦10 ms＋tripping time of operating circuit-breakers +standby circuit-breaker closing time (to be calculated from the closure of external protective pickup contacts to the closure of standby circuit-breakers)

10.4 Monitoring and Display function

The LCD displays the following parameters or states:

1) Three-phase voltage of auxiliary power busbar: Ua, Ub and Uc or Uab, Ubc and Uca。

2) Operating power voltage Ugz (any one phase voltage or any one line voltage at plant transformer branch or generator terminals)

3) Standby power voltage Ubz (any one phase voltage or any one line voltage on HV or LV sides of standby transformers)

4) Frequency of station busbar voltage Ua (or Uab) and standby power voltage (Ugz or Uby)。

5) Frequency difference between station busbar voltage Ua (or Uab) and standby power voltage (Ugz or Uby)。

6) Phase difference between station busbar voltage Ua (or Uab) and standby power voltage (Ugz


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or Uby)。

7) Three-phase current Igz of operating branches (any phase current or line current)

8) Three-phase current Ia, Ib and Ic of standby branches.

9) Status of operating circuit-breakers, backup circuit-breakers and station busbar PT’s isolator.

10) All set parameters

11) Status of all external links and internal soft links

10.5 Changeover function

10.5.1 Normal changeover

Normal changeover is manually initiated from control desks, DCS systems or device panels.

Normal changeover is bidirectional, that is to say, the operational (standby) power source may be changed over to the standby (operational) power source.

There are the following several normal changeover modes:

10.5.2 Parallel changeover

(1). Parallel changeover, automatic

It is manually initiated. If the conditions for parallel changeover are met, the device will firstly close the standby (operational) circuit-breakers and then trip the operational (standby) circuit-breakers after a delay time. If the standby (operational) circuit-breaker, which has just been closed, is tripped within the delay time, the device will not continue to trip the operational (standby) circuit-breaker. If the conditions are not met after changeover initiation, the device will block signal sending and wait for manual resetting.

(2). Parallel changeover, semi-automatic

It is manually initiated. If the conditions for parallel changeover are met, the device will close the standby (operational) circuit-breakers and the operational (standby) circuit-breakers will be manually operated. If operators don’t trip the operational (standby) circuit-breaker within the preset time, the device will generate an alarm so as to prevent two power sources from being parallel connected for a long time. If the conditions are not met after changeover initiation, the device will block signal sending and wait for manual resetting.

10.5.3 Normal tandem changeover

It is manually initiated. A command to trip the operational (standby) circuit-breaker will be firstly issued. After confirming that the operational (standby) circuit-breaker has been tripped and the changeover conditions are met, close the standby (operational) circuit-breakers. Normal changeover is used for two power source units with a large intrinsic phase difference between difference frequency system or common frequency systems. This mode may be achieved in four ways, rapid changeover, synch capture, residual voltage and long delay time. If rapid changeover fails, the device will automatically enter synch capture, residual voltage and long delay time status.

10.5.4 Normal simultaneous changeover

Normal simultaneous changeover is manually initiated and a tripping command and closing command will be simultaneously issued. Because the closing time is generally longer than the opening time, a delay time may be set before issuing closing commands so that circuit-breaker opening is performed earlier than circuit-breaker closing. It is applicable to changeover between common and differential frequency systems. This mode may be achieved in four ways, rapid changeover, synch capture, residual voltage and long delay time. If rapid changeover fails, the device will automatically enter synch capture, residual voltage and long delay time status.

10.5.5 Emergency changeover

Emergency changeover is initiated by a protective output and the operational power source is


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changed over to the standby power source.

There are two emergency changeover ways:

Emergency tandem changeover

It is initiated by a protection. The operational power circuit-breaker is firstly tripped. After confirming that the operational circuit-breaker has been tripped and the changeover conditions are met, close the standby power circuit-breaker.

There are four ways used to perform tandem changeover, rapid changeover, synch capture, residual voltage and long delay time. If rapid changeover fails, the device will automatically enter synch capture, residual voltage and long delay time status

Emergency simultaneous changeover

It is initiated by a protection. Firstly issue a command to trip operational power circuit-breaker. When the changeover conditions are met (or after a preset delay time), a command is issued to close the standby power circuit-breaker. There are four ways used to perform emergency changeover, rapid changeover, synch capture, residual voltage and long delay time. If rapid changeover fails, the device will automatically enter synch capture, residual voltage and long delay time status

10.5.6 Abnormal changeover

In case a abnormal condition is detected by a device, abnormal changeover is automatically initiated and the operational power source is changed over to the standby power source.

Abnormal conditions include the following two conditions:

Auxiliary power busbar loss of voltage

When three-phase voltage of auxiliary power busbar is lower than a set value and the current is equal to or smaller than a set value for more than a set delay time, the device will perform tandem or simultaneous changeover depending on chosen modes.

Changeover ways: rapid changeover, synch capture, residual voltage and long delay time

Incorrect operational power circuit-breaker tripping

If the operational power circuit-breaker is incorrectly tripped due to various reasons (including incorrect operation and operating mechanism failure), the device will close the standby power circuit-breaker provided that the changeover conditions are met.

Changeover ways: rapid changeover, synch capture, residual voltage and long delay time. The device provides auxiliary current judgment functions

10.6 Load Reduction in case of Low Voltage

The load reduction for low voltage is effective only when the device is performing changeover.

Temporary power failure during changeover will cause the drop in auxiliary power busbar voltage and motor speed. Whether motor groups can successfully start up after closing standby power circuit-breakers mainly depend on the auxiliary power busbar voltage. In this case, some common auxiliaries may be cut off, This is advantageous to self-starting of key auxiliaries. The device may have 2-section load reduction output and a delay time may be set for the two sections respectively.

10.7 Alarm block and failure processing function


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As shown in the figure, changeover blocking is a general block status. In case of any of device failure, abnormal circuit-breaker position, protection blocking, broken PT, device actuation, loss of power blocking, disabling hard link changeover, disabling soft link changeover and disabling all changeover, the device will be in changeover blocked state and therefore it is impossible to perform changeover.

The above blocking reasons may be divided into two major categories: (1) block which can be automatically reset; (2) blocks which can not be automatically reset. The former refers to that the device can be in normal state after the block conditions disappear. The latter refers to that the device returns to the normal operating state after the block conditions disappear and the device is manually reset. The block modes are described in detail below

(1). Blocking which can be automatically reset

Blocking in case standby power failure: When the control word “Blocking in case of Standby Power Failure” is ON and the standby power voltage is smaller than the set "Lower Voltage Limit", the device will be blocked. Notes: if the control word is OFF and the standby power voltage is smaller than the set lower limit, the changeover will not be blocked and only residual voltage changeover or changeover with a long delay may be performed.

Hard changeover link OFF: When the digital input “Changeover ON/OFF” contact is in closed state, the changeover functions will be blocked.

Soft changeover link OFF: When the control word “Changeover ON/OFF” is set to OFF, the changeover functions will be blocked.

All changeover modes are OFF: when the control words “Fast Changeover”, “Synch Capture Leading Phase Angle”, “Synch Capture Leading Time”, “Residual Voltage Changeover” and “Changeover with a Long Delay” are OFF, the changeover will be blocked.

(2). Blocking which can not be automatically reset

Device failure: When a failure is detected during self-testing course, the changeover function will be blocked.

Abnormal circuit-breaker position: If the operational and standby circuit-breakers are not consistent (both circuit-breakers are closed or opened), or the device considers circuit-breaker positions as abnormal when the PT isolator is opened, the changeover function will be blocked.

Protective blocking: When the external digital input “Protective Blocking” is ON, the changeover


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functions will be blocked.

Broken PT: The fast changeover device judge a broken PT wire by analyzing voltage. If a PT wire is broken, the fast changeover functions will be blocked.

Device operation: When the device has been actuated, the changeover function will be blocked. The device may return to the normal operation only after being manually reset.

10.8 Abnormal Circuit-breaker Positions (Position Blocking/Decoupling)

One of necessary conditions for changeover actuation is that one of the operational and standby circuit-breakers is closed and another is opened and the PT’s isolator must be in closed position. If the condition is not met (except for incorrect tripping), the device will block its output, issue “Device Blocked” signal to the CCR and wait for resetting.

If a circuit-breaker fails to open or close within certain time, the device will deal with the situation depending on changeover ways and issue blocking signals. For example, if, during simultaneous or parallel changeover, a circuit-breaker cannot be tripped, two power sources will be parallel connected. In this case, the device will execute decoupling function so that the circuit-breaker which is just closed is tripped.

10.9 Device Self-test Failure

After operation, the device always perform self test on some key components, such as CPU, RAM, EEPROM and AD. Once any abnormal condition is detected, the changeover function will be blocked, the “Device Failure” signal will be sent and the device will wait for resetting. When the CPU failures in the worst case, it is impossible to perform self test and block the device.

10.10 Protective Blocking

Changeover is blocked due to an external digital input. When certain protections (such as HV auxiliary transformer branch overcurrent and busbar protection etc), the device blocking will be initiated by the protective outputs so as to prevent standby power source from being connected to failure busbar,. In this case, the device will send “Protective Blocking” signals and wait for resetting.

Notes: The status of waiting for resetting is an operating state and not a central control signal. Once the device sends a “Device Blocked” signal, the device will be necessarily in the status of waiting for resetting. In this case, the changeover is impossible. When the device is manually reset and the block conditions don’t exist, the device can be in operating state and the next changeover is possible.

10.11 PT Breakage

When one or two phases of auxiliary power busbar PT is broken, the device will block alarms and be ready for resetting.

10.12 Standby Power Failure Monitoring

If the standby (operational) power source fails when the operational (standby) power source is put into operation, it is impossible to perform changeover operation and the device will generate an alarm and is ready for resetting.

Notes: The function may be enabled or disabled in the Mode Setting menu taking account of the need for standby section PT maintenance. After the “Changeover Blocked upon Standby Power Failure” is disabled, the device can still perform residual voltage changeover and changeover with a long delay provided that the standby power exists.

10.13 Unblocking

All device blocking may be released except for standby power failure only after abnormal conditions don’t exist and an alarm is manually reset.

If the Changeover Blocked upon Standby Power Failure is enabled and standby voltage loss is detected, the device will block changeover. When the standby voltage is recovered, the device will release blocking without the need for manual resetting.


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10.14 Protection Speedup Functions

When the device initiates any changeover, it will output a closed contact signal so that the branch protection can be speeded up.

10.15 Daily Maintenance

10.15.1 Alarm window or DCS signal

When the auxiliary power supply system and device are in normal operation, the alarm windows will not turn on. When they malfunction, one or more alarm windows will turn on. This condition should be dealt with case by case. Then, press the RESET button to reset alarm windows.

Device power failure: Check the DC power voltage of the device and check whether the DC fuse of the rapid changeover cabinets is in good order, the air circuit-breaker on cabinet rear panel is closed, and the power module switch is opened. If they are in order, check the +5, +15, -15 and +24V lamps on power module front panels to confirm which circuit failures. If a problem exists inside the device (including power modules), immediately deal with it or notify maintenance personnel.

Changeover blocked. This is a general signal indicating that the changeover is blocked due to a certain cause. The cause should be investigated taking account of the Status Report menu on other alarm windows or LCD. The possible causes include:

Changeover in progress. The device changeover is in progress.

PT breakage. It indicates that one or two phase voltage input to the device is too low due to PT breakage.

Protective blocking. It indicates that the device receives external "Protective Blocking” command, namely the "Protective Blocking” contact was closed. Check the protections.

Blocking initiated by standby power failure. When the blocking function is enabled and the standby power fails, the changeover functions will be blocked.

Device failure: The alarm window indicates that the device detects a failure in a major component during self test. Immediately inform the manufacturer.

Abnormal circuit-breaker position. When the PT isolator is not closed and the position is blocked, the alarm window will turn on.

Changeover disabled. It indicates that the changeover functions are manually disabled.

Daily panel check

When the device is in normal operation, only one of the Operational Power lamp or Standby Power lamp remains On, the Device Run lamp is blinking, the Remote Operation lamp remains On and the Changeover Operation lamp and Blocking lamp remain Off.

Measurement indication: The indicated voltage, current, frequency, frequency difference, phase difference and circuit-breaker positions should be consistent with the actual states.

Mode setting: All mode setting should be in accordance with the setting.

Setpoint: All set values should be consistent with the setpoint.

Abnormal event: no abnormal event currently occurs.

Status report: no abnormal state

Status bar: the clock can be displayed, the operating mode is consistent with the setting value and no blocking icon is displayed.

10.16 Failure Analysis

When the rapid auxiliary power changeover device is in normal operation, there is not any alarm signal. Once an alarm is active, immediately deal with it or notify maintenance personnel. After treatment, press the RESET button so as to put the device into operation.


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Device power failure: Check that the DC power supply is in order;

Device blocked: it is a general signal indicating that the device is blocked due to a reason, which should be investigate taking account of other signals.

Changeover over: indicating that the changeover is successfully completed.

PT breakage. It indicates that one or two phase voltage input to the device is too low. Immediately notify maintenance personnel.

Protective blocking: indicating that the device receives a “Protective Blocking” command. Check the protection.

Standby power failure: When the blocking function is enabled and the standby power fails, the changeover functions will be blocked.

Device failure: indicating that the device detects a failure in a major component during self test. Immediately inform maintenance personnel and contact the manufacturer.

Abnormal circuit-breaker position: indicating that the external input contact is incorrect. Immediately notify maintenance personnel.

10.17 Selection of 6kV Auxiliary Power Supply System Changeover Mode for #31, #32 and #33 Units

Simultaneous changeover is adopted for normal changeover of 6kV busbar for #31, 32 and 33 units. A manual starting button, remote changeover mode selective button, device blocking setting button, output blocking setting button and remote reset button are provided in the DCS. Local changeover may be performed on the rapid changeover panel. The fast changeover device must be reset after each actuation so as to put it into standby state and check any possible alarms. If a abnormal condition is found, contact maintenance personnel.

Normal changeover is bidirectional, that is to say, the operational (standby) power source may be changed over to the standby (operational) power source. Normal simultaneous changeover is adopted for 6kV auxiliary power supply system for #31, 32 and 33 units.

It is manually initiated. A command is firstly issued to trip the operational (standby) circuit-breaker. When the changeover conditions are met, a command is issued to close the standby (operational) circuit-breaker. This will ensure that a auxiliary power circuit-breaker is closed after another circuit-breaker is opened. A closing delay time may be set.

There are four conditions for normal simultaneous changeover, rapid changeover, synch capture, residual voltage and changeover with a long delay. If rapid changeover fails, synch capture, residual voltage changeover and changeover with a long delay will be automatically performed.

11 6kV Auxiliary Power Supply System Protection and Automatic Device 6kV system protection and automatic device is composed of Series WDZ400 microprocessor-based automation protection and devices manufactured by Jiangsu Jinzhi Electrical Co., Ltd. WDZ430 motor protection and control device, WDZ431 differential protection and WDZ410 line protection and control device and WDZ440 transformer protection and control device are used in the power plant.

11.1 Application of Series WDZ4OO Microprocessor-based protection in the plant

Equipments Model 6kV motor with a capacity up to 2000kW WDZ430 6kV motor above 2000kW WDZ431、WDZ430 6kV feeder switch cabinet WDZ410 HV side switch cabinet for 6kV auxiliary transformer WDZ440 6kV harmonic cancellation device WXZ196 6kV motor protection and communication manager ECM5906


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6kV PT protection cabinet WDZ491

11.2 WDZ-430EX Motor Protection and Control Device

WDZ-430EX motor protection and control device (the Device) is mainly used to protect and control large-or medium-sized three-phase asynchronous motors. For extra large-sized motors (2000kW and higher, or the main protection sensitivity does not pass verification), WDZ-431EX differential motor protection should be mounted. The device may be provided with separate operating circuits and anti-bounce circuits and is suitable for use with motor circuits with different outputs.

11.2.1 Main protective functions:

Current instantaneous tripping protection (reverse power block)

Negative-sequence overcurrent protection (for section I)

Negative-sequence overcurrent protection (for section II)

Earth failure protection

Overheating protection

Restart inhibition protection

Locked rotor protection

Long starting time protection

Positive-sequence over-current protection

Overload protection

Under-voltage protection

PT breakage alarm

Output blocking in case of a large current in FC circuit

Fuse protection

Separate operating circuit and anti-bounce circuit (optional)

Disturbance record and motor starting process record

11.2.2 Main measurement and control functions

10-way remote digital input acquisition, internal remote signals and emergency remote signal

Remote circuit-breaker tripping and closing

Remote measurement: three-phase voltage, three-phase current, P, Q, power factor and frequency

2-way impulse input which facilitate meter recording

A high-accuracy smart watt hour meter with active impulse output is built in the device and external watt hour meter is not required (optional)

1-way 4-20mA analog output which replace transmitters and is used as a measuring port with DCS (optional)

Motor start information and start counts

11.2.3 Operation and control functions

The operating circuits are protected against bouncing and a appropriate number of position contacts are provided. The device is able to block tripping and closing functions to suit to circuit-breakers having different operating mechanisms (such as hydraulic, pneumatic, energy storage by motor or spring). Changeover between local/remote controls can be performed upon the users’ demand. The device has 12-way digital input and 8-way digital output circuits and soft or hard logic interlock


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control may be performed.

11.2.4 Remote functions

Many communication ports: RS485, CAN, Ethernet ports, which support dual net and remote measurement, remote signal, remote control and remote adjustment.

11.2.5 Daily maintenance

a) Device startup

Turn of the DC power source. The RUN/COMMISSIONING lamp flashes and other lamps remain off.

Check the device setting against the setpoint list;

Check that the voltage and current inputs are correctly wired.

b) Device operation

The RUN/COMMISSIONING lamp flashed;

The current and voltage indicated on the device panel should be equal to their actual values;

The digital input status should be identical to the actual status.

c) Protection action signal and report

If the motors are tripped, the device output lamp will turn on and remain on, an alarm will be generated and displayed on the screen. If an abnormal operating condition caused protection action, an alarm will be generated and displayed on the screen. In case of overload or earth failures, the corresponding lamps will turn on. All of the above situations may be printed out via communication ports.

When an alarm is active, the output lamp will turn on and the protective functions are still effective. Analyze the causes of the problems. After the cause is eliminated, press the RESET button to clear alarms.

11.3 WDZ-431 EX Motor Differential Protection

WDZ-431EX differential motor protection (hereinafter referred to as the device) is mainly used as differential protection for large-sized three-phase asynchronous motors (2000kW or higher, or the sensitivity of main protection is unacceptable) and constitutes a complete motor protection together with WDZ-430EX general motor protection.

11.3.1 Main protective functions (each protective function may be enabled or disabled and operating circuits may be chosen according to the actual demands):

Differential instantaneous tripping protection

Differential ratio protection for respective phase

Setpoint multiplication

Differential blocking and alarm in case of CT breakage

Disturbance recorder

11.3.2 Auxiliary functions

1） If a failure is not cleared after protection action, other protections will also be triggered provided that the conditions are met.

2） If a failure occurs when the protection is actuated and not reset, the protection can also be actuated. That is to say, the protection can be actuated several times.

3） The device is able to record various information about operation of the device and motors, including:


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64 protective SOE events

256 remote position change SOE events

16 self-diagnostic events

4） The disturbance recorder is able to record all analog and digital signals associated with one latest failure, including:

Data during two cycles before failures, four cycles after tripping and in failure. The max. Recording time is 10s.

11.4 WDZ-410EX Line Protection and Control Device

WDZ-410EX line protection and control device (hereinafter referred to as the device) is mainly used to protect and control feeders, branches or busbar sections. A separate operating and anti-bounce circuit may be provided for the device.


Current instantaneous tripping protection (overcurrent section I blocking in case of low voltage)

Current instantaneous tripping protection with a delay (overcurrent section II blocking in case of low voltage)

Overcurrent protection (overcurrent section III)

Earth failure protection (zero-sequence overcurrent protection)

Overload protection

Post-acceleration protection



11.4.2 Main measurement and control functions (each digital I/O may be enabled or disabled and operating circuits may be chosen according to the actual demands):





A high-accuracy smart watt hour meter with active impulse output is built in the device and external watt hour meter is not required (optional)


11.5 WDZ-440EX Transformer Protection and Control Device

WDZ-440EX LV transformer protection and control device is mainly used to protect and control LV transformers (10KV/380V or 6KV/380V). For extra large-sized LV transformers (5600kVA and higher, or the main protection sensitivity is unacceptable), WDZ-441EX LV transformer differential protection should be mounted. The device may be provided with separate operating circuits and anti-bounce circuits and is suitable for use with transformer circuits with different outputs.



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Current instantaneous tripping protection for HV side

Current instantaneous tripping protection for HV side, with a delay

HV side overcurrent protection

HV side overload protection (with regard to time characteristics, the definite time, normal inverse time, very reverse time or extraordinary reverse time may be chosen)

V side negative-sequence overcurrent section I protection

HV side negative-sequence overcurrent section II protection

HV side earth failure protection (definite time zero-sequence overcurrent protection)

LV side zero-sequence overcurrent protection (with regard to time characteristics, the definite time, normal inverse time, very reverse time or extraordinary reverse time may be chosen)

Non-electrical protection (digital input)

Output blocking in case of a large current in FC circuit

Fuse protection



11.5.2 As a smart front-end, it has the following main measurement and control functions (each digital I/O may be enabled or disabled and operating circuits may be chosen according to the actual demands):





A high-accuracy smart watt hour meter is built in the device and external watt hour meter is not required (optional)


12 380V Auxiliary Power Supply System Protection and Control Device 12.1 Smart Controller

The smart controller is a core of Series RMW1 smart frame-type circuit-breakers and the control part of overload protection, short-circuit protection, earth failure protection and other protections.

The core of controllers is a 16-bit high-speed microprocessor. The mechanical actuator is a magnetic flux transducer which is independent from under-voltage and shunt release. Normally, a permanent magnet attracts the core and the transducer is in closed state. When the controller issues a actuation command, the reversing field will overcome the magnetic flux of the permanent magnet, the return spring opens the moving core, the magnetic flux transducer is opened and therefore the circuit-breaker is opened.

Meaning of parameter symbols on the panel:

In Rated current of circuit-breaker Ir1, Ir2, Ir3, Ir4 Delayed tripping current (including long and short delay time),

instantaneous tripping current and earth failure current Tc1, Tc2, Tδ, TG, Tl, Ts Set Load 1, Load 2, unbalance, earth, long delay time and short delay 1, 2, 3, N Phase A, B, C and N Hz, kW, V Frequency, power and voltage


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cosφ Power factor L1, L2, L3, G Indicating Phase A current, Phase B current, Phase C current and earth

current ％, A/kA, s, I2t Percentage, ampere /kilo ampere, second, definite time or reverse time Ic1, Ic2 Set current for load monitor 1 and 2 δ Three-phase (A, B and C) current unbalance rate If Set earth failure current L, S, I Set long delay time, short delay time and transient time T Self-diagnostics ER1～ER4 Self-diagnostic error code

12.2 Smart MCC Control12.2.1 Device and Protection

12.2.1 Device function

The device is able to measure IA, IB, IC, I0, positive-sequence, negative-sequence, thermal state and other physical quantity.

Remote and local control can be performed.

Programmable interlock logic

Self-start after voltage recovery

Thermal protection and restart inhibition protection

Earth failure protection

12.2.2 Device panel

1) LED windows

A 6-digit LED window indicates motor current and thermal state. The motor thermal state is indicated in percentage. When the motor attains thermal balance state, the value is zero. When the value is 100, the motor has attained the set overheating state and the thermal protection will be initiated.

2) Indicating lamp

RUN――― remains On when the motor is in operation (red)

STOP――― remains On when the motor stops (Green)

Overheated――― remains On after the overheating protection is actuated; and turns Off when resetting failures

EARTH――― remains On after the earth failure protection is actuated; and turns Off when resetting failures

INTERLOCK ON―― when the standby motors are started up, the lamp flashes (red) to prompt operators to push the OPERATIONALSTANDBY changeover switch to OPERATIONAL.

Device failure ――― remains on (red) when the device failures, and turns off when the device is in order.

COMMUNICATION――― The identification on the panel is COMMUNICAITON when the device is in ModBus communication mode. When the device is in normal communication, the lamp flashes (red). The identification on the panel is PB FAILURE when the device is in ProfiBus communication mode. When the device is in normal communication, the lamp turns off. When the communication fails, the lamp turns on (red).

3) Touch keypad

Keys: “+, －, SELECTION, ACK, CANCEL and RESET”.

“+” and “－” keys are used to modify set values;


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The SELECTION key is used to select among setting values.

The ACK and CANCEL key is used to confirm and cancel a operation.

The RESET key is used to re-start the device.

In addition, the CANCEL key may be used to reset alarms. When a motor failure occurs, the failure signal will be held. It is possible to restore the normal operation of motors only after the failure signals are reset. The failure signals may also be reset using programmable input or Fieldbus communication.

4) Pushbutton

There are local control pushbuttons on the device panels.

Red motor START pushbutton

Green motor STOP pushbutton

The device controlling reversible motors (such as MKB-200) has two START pushbuttons, START A and START B. Use START A pushbutton to run the motors in normal direction and use START B pushbutton to reverse the direction of rotation.

5) OPERATIONAL /STANDBY selective switch

There is an OPERATIONAL/STANDBY selective switch on the panel. Use the switch to set the motor to the operational or standby state. When some of two or more motors are used as the operational ones and another motors are used as standby, the selective switch must be used.

6) REMOTE/LOCAL selective switch

There is a LOCAL/REMOTE selective switch on the panel. The switch is used to choose between local and remote control. When the switch is in LOCAL position, the control buttons on the panel can be used to control motors and the remote control (refer to external control buttons connected with device terminals and Fieldbus-based control functions, not including programmable input interlock functions) is ineffective. When the switch is in the REMOTE position, the device can be remotely controlled (refer to external control buttons connected with device terminals and Fieldbus-based control functions) and the control buttons on the panel is ineffective.

13 Explanation of Some Operations for ECS System (Electrical Control System) of the DCS 13.1 Scope

The ECS concerns the operation of rapid auxiliary power changeover device, microprocessor-based synchronizer as well as generator startup and shutdown. The operation menus provide a MMI for operators.

The menu is divided into pop-up menus (which pop up when operators click devices on DAS menu) and disabling menus.

13.2 Typical Operation

13.2.1 Rapid changeover device

Click “DEV/QUIT” for putting the quick switching device into operation

Click “RESET” for resetting the quick switching device

Click “PAR” or “SEQ” for selecting the quick switching mode as ‘parallel’ or ‘sequence’.

Click “ACTIV” for executing the quick switching

Click “RESET” for resetting the quick switching device

13.2.2 Circuit breaker

An operation panel of common circuit-breakers is composed of CLOSING, OPENING, ACK and


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failure indication buttons. When clicking the CLOSING or OPENING button, the ACK button will spear on the screen. After clicking the ACK button, the system will send a 2s short pulse to operate the circuit-breakers and the ACK button will be highlighted. If the opening or closing conditions are met, the box under the CLOSING or OPENING buttons will turn red. If a failure exists, the box will turn yellow. If no failure exists, the box will turn grey.

13.2.3 Automatic quasi-synchronizer

The operation panel is composed of buttons of “ENGAGE”, “RESET”, “CHOOSE GS101/GS102” and “QUIT”.

Click “RESET” for resetting the synchronizing device.

Click “GS101/GS102” for choosing the synchronizing object.

Click “ENGAGE” for engaging and starting the synchronizing device, synchronized with the system of the synchronization conditions are met.

Click “QUIT” for stopping the automatic quasi-synchronizer

13.2.4 Generator side/interrupting circuit-breaker (150KV unit main/bypass circuit-breaker)

Log in the NCS operating interface, select the GS101/GS102 switch to execute the trip. After the rechecking of the NCS system is normal, execute the tripping order. Check and make sure the tripping position and the messages are normal.

13.2.5 Generator AVR

There are 4 buttons, EXCITATION INCREASE/DECREASE, EXCITAITON ON/OFF, OPERATING MODE and PSS buttons, on the flow diagram. After clicking the EXCITAITON ON/OFF buttons, the ACK button will appear on the screen. After clicking the ACK button, the system will send a 2s short pulse and the ACK button will be highlighted. After clicking other buttons, the system will directly send pulses. After clicking the CONSTANT GENERATOR TERMINAL VOLTAGE on the OPERATING MODE SELECTION, the constant generator terminal voltage mode will take effect. After then, the button will become CONSTANT GENERATOR VOLTAGE OPERATION OVER. After clicking it, the operating mode will stop.

13.2.6 Startup and shutdown sequence for generator and diesel-engine generator

Click the START button to start program control.

The current program control sequences will be highlighted on the panel.

Observe the corresponding conditions, status and equipment actions on the panel. If certain step need be confirmed by operators, the ACK button will appear on the panel. Click the ACK button to confirm the operation.

If necessary, press the ESC button to exit program control.

If a step has timed out, the system will automatically exit program control.

There is a side/middle circuit-breaker selective button in the generator starting process. Click the SELECT Q 5022 or QF5021 to select circuit-breakers. Then, a ACK button will appear on the panel. Click it to confirm the choice.

There is a shutdown mode selective button in the generator shutdown program. Click the CLOSING MSV or CUTTING 3DL button to select shutdown modes.

13.2.7 Equipment operation inhibition

When equipments are maintained or locally operated, prevent operators from sending operation commands from the CRT. For this purpose, a “Operation Inhibition” function is provided for the system. Operation inhibition may only be completed on the OPERATON INHIBITION MENU. After clicking certain equipment from the menu, a corresponding OPERATION INHIBITION manipulator will pop up. Click YES to inhibit equipment operation. After then, the manipulator of


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this equipment can not pop up on the flow diagram. Click NO to release operation inhibition. In this case, the operation inhibition lamp will turn grey.

13.3 DCS System Failure

13.1.1 Phenomenon

The real-time parameter refresh failure;

Closed-loop controller failure, regulating property deterioration;

Divergent regulating property;

Controller actuator failure.

13.1.2 Solution

If operators are uncertain how to deal with DCS failures or a failure has seriously endanger the safe operation of the units, never sustain unit operation, but immediately shut down the generators, steam turbine and boiler using hard-wired manual panels;

In case all operator stations failure ("black screen" or “crash” occur in all host computers), immediately shut down the units.

If some operator stations failure, the available operator stations should continue to accomplish supervisory control (stop any major operation) and rapidly eliminate failures. If impossible to clear failures, operators should deal with the situation depending on the current operating conditions.

When some operator stations failure and it is impossible to eliminate such failures, shut down the generators after obtaining the approval from dispatchers.

When the regulating circuit controller or power supply fails, change over operating mode from auto to manual, sustain unit operation, rapidly deal with system failures and take appropriate actions according to the specific situations.

Electrical Operation Manual handbook

Documents

shutdown of generator

cooling system of generator

generator excitation

generator nameplate

structure of generator

primary wiring system

electrical operation

auxiliary power system