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“Design of 400/220kV Sub-station” S.M. MUJUMDAR General Manager (sub-station Engineering) 27 th April 2005 Jyoti Structures Ltd., Mumbai
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Design of 400-220kV Substation

Sep 09, 2014

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Page 1: Design of 400-220kV Substation

“Design of 400/220kV Sub-station”

S.M. MUJUMDARGeneral Manager

(sub-station Engineering)

27th April 2005 Jyoti Structures Ltd., Mumbai

Page 2: Design of 400-220kV Substation

Agenda

Overview of 400kV sub-station

Design Process

Design considerations

Question / Answer

Page 3: Design of 400-220kV Substation

Imp. considerations in substation design

Safety of personnel and equipment Reliability and Security Adherence to

Statutory obligations

– I.E. rules, Environmental aspects Electrical design considerations Structural design considerations

Ease of maintenance Possibility to Expand

Page 4: Design of 400-220kV Substation

System parameters

1000 mV

(156kV)

1000 mV

(320kV)

Radio interference voltage at 1MHZ (for phase to earth voltage)

10.

40kA40kARated short ckt. Current for 1 sec.8.

25mm/kV25mm/kVMin. creepage distance7.

156kV320kVCorona Extinction voltage 6.

Effectively earthedSystem neutral earthing5.

33Number of phases4.

50Hz50HzRated frequency3.

245kV420kVMax. operating voltage2.

220kV400kVNominal system voltage1.

220kV400kVDescriptionSr.

Page 5: Design of 400-220kV Substation

System parameters Contd..

Remarks220kV400kVDescriptionSr.

(Line-ground)

(open terminals)

460kV

460kV

530kV

460kV

680kV

520kV

610kV

630kV

iii) One min. power freq.

withstand voltage (dry/wet)

-- for lines

-- for CB / Isolator

-- for other equipments

1050kVpii) Switching impulse

withstand voltage (dry/wet)

1050kVp

950kVp

1050kVp

1550kVp

1300kVp

1425kVp

Rated insulation levels

i) Full wave impulse

withstand voltage

-- for lines

-- for reactor/ X’mer

-- for other equipments

11.

Page 6: Design of 400-220kV Substation

Substation Bird’s view

Page 7: Design of 400-220kV Substation

400kV Circuit Breaker

Page 8: Design of 400-220kV Substation

400kV Isolator

Page 9: Design of 400-220kV Substation

400kV Current Transformer

Page 10: Design of 400-220kV Substation

400kV CVT

Page 11: Design of 400-220kV Substation

400kV Surge Arrester

Page 12: Design of 400-220kV Substation

Shunt Reactor & NGR

Page 13: Design of 400-220kV Substation

400/220 kV Auto Transformer

Page 14: Design of 400-220kV Substation

400kV Bus Post Insulator

Page 15: Design of 400-220kV Substation

Wave Trap

Page 16: Design of 400-220kV Substation
Page 17: Design of 400-220kV Substation

Functions of substation equipments

To discharge lightning over voltages and switching over voltages to earth

7. Lightning Arrester

To step-down voltages for measurement, control & protection

6. Voltage Transformer

To step-down currents for measurement, control & protection

5. Current Transformer

To discharge the voltage on dead lines to earth4. Earthing switch

Disconnection under no-load condition for safety, isolation and maintenance.

3. Isolators

Automatic switching during normal or abnormal conditions

2. Circuit Breaker

Incoming & outgoing ckts. Connected to bus-bar1. Bus-Bar

FunctionEquipment

Page 18: Design of 400-220kV Substation

Functions of substation equipments Contd…

Compensation of long lines.14. Series Capacitor

To step-up or step-down the voltage and transfer power from one a.c. voltage another a.c. voltage at the same frequency.

13. Power Transformer

To provide compensations to reactive loads of lagging power factors

12. Shunt capacitors

To prevent high frequency signals from entering other zones.

11. Line –Trap

To provide connection between high voltage line & PLCC equipment

10. Coupling capacitor

To limit earth fault current9. Neutral-Grounding resistor

To control over voltages by providing reactive power compensation

8. Shunt reactor

Page 19: Design of 400-220kV Substation

Functions of Associated system in substation

3. Illumination system (lighting)

-- for switchyard

-- buildings

-- roads etc.

To protect the outdoor substation equipment from lightning strokes.

2. Overhead earth wire shielding or Lightning masts.

To provide an earthmat for connecting neural points, equipment body, support structures to earth. For safety of personnel and for enabling earth fault protection. To provide the path for discharging the earth currents from neutrals, faults, Surge Arresters, overheads shielding wires etc. with safe step-potential and touch potential.

1. Substation Earthing system

-- Earthmat

-- Earthing spikes

-- Earthing risers

FunctionSystem

Page 20: Design of 400-220kV Substation

Contd..

To provide alarm or automatic tripping of faulty part from healthy part and also to minimize damage to faulty equipment and associated system.

4. Protection system

-- protection relay panels

-- control cables

-- circuit breakers

-- CTs, VTs etc.

For Protective circuits, control circuits, metering circuits, communication circuits

5. Control cable

For communication, telemetry, tele-control, power line carrier protection etc.

7. PLCC system power line carries communication system

-- line trap

-- coupling capacitor

-- PLCC panels

To provide supply path to various auxiliary equipment and machines.

6. Power cable

Page 21: Design of 400-220kV Substation

Contd…

To sense the occurrence of fire by sensors and to initiate water spray, to disconnect power supply to affected region to pin-point location of fire by indication in control room.

8. Fire Fighting system

-- Sensors, detection system

-- water spray system

-- fire prot. panels, alarm system

-- watertank and spray system

For internal and external communication

10. Telephone, telex, microwave, OPF

For supplying starting power, standby power for auxiliaries

9. Auxiliary standby power system

-- diesel generator sets

-- switchgear

-- distribution system

Page 22: Design of 400-220kV Substation

Basic drawings for design/construction

Single Line Diagram

General Arrangement Drawing

Electrical Plan and Section

Control Room Architectural layout

Page 23: Design of 400-220kV Substation

Supporting drawings

Structural layout

Earthmat layout

Civil layout

Erection Key Diagram

Lighting Layout

Page 24: Design of 400-220kV Substation

Single Line Diagram – 220kV

Page 25: Design of 400-220kV Substation

General arrangement layout

Page 26: Design of 400-220kV Substation

Electrical layout

Page 27: Design of 400-220kV Substation

Electrical Section

Page 28: Design of 400-220kV Substation

Control room layout

Page 29: Design of 400-220kV Substation

Control room layout

Page 30: Design of 400-220kV Substation

Structural layout

Page 31: Design of 400-220kV Substation

Earthmat Layout

@

@

@

@

@

@

@

@

@

Page 32: Design of 400-220kV Substation

Civil layout

Page 33: Design of 400-220kV Substation

Erection Key Diagram

EW2EW2

4S1

4S1

4DTTM-2

EW1

4I

4S1

4LA 4P 4V4S1 4W4W

4S14S1

4I

4S1

4LA4S1

R1

4SSTM-D

4T14T14T1

4S1 4S14S1

EW2EW2

4S1

4S1

4S1

4DTTM-1 4S24S2 4S2

EW1

4SSTM-D

4TBSM4TBSM 4TBSM

4P14I4P34S1 4S1

4P14I4IC1

4S1 4S14S1

4B4I2 4I14I4IC2

4S1

4C24C1 4I14B

EW2EW2

4SSTM-T

4S2 4S24TM

4S1 4S14S1

4DTTM-14DTTM-2

EW1

4S24S2 4S2

4I2

4S1

4IC2

4DTTM-1

4DTTM-1

4DTTM-1

4DTTM-1

4DTTM-1

4DTTM-1

4SSTM-D

4LA

4P

4P

4P

4LA

4LA

4W

4V

4V

4V

4W

4SSTM-D

4DTTM-1

4DTTM-1

4DTTM-1

4SSTM-D

4I

4I

4I

4I

4I

4I

4W

4P

4V

4LA

4P

4LA

4V

4P

4LA

4V

4W

4SSTM-D

4DTTM-1

4DTTM-1

4SSTM-D

4I

4I

4I

4I

4DTTM-1

4I

4SSTM-D

4I

4P3

R1

R1R1

4LA

4LA

4LA

4DTTM-2

4P3

4P3

4I

4I

4I

4DTTM-2

4I

4I

4DTTM-2

4I

R1

R1

R1

4LA

4LA

4LA

4P3

4P3

4I

4I

4DTTM-2

4DTTM-2

4I

4I

4P3

4I

4DTTM-2

4I

4B

4B

4B

4DTQB-24DTQB-2 4DTQB-2

4I2

4I1

4I

4P1

4IC2

4P1

4IC1 4I2

4I1

4I1

4B

4B

4B

4C2

4C1

4I1

4I2

4C2

4C1

4I1

4I2

4C2

4C1

4I1

4I2

4B

4B

4B

4P1

4I2

4I14IC2

4P1

4IC1

4I2

4I1

4I

4DTQB-14DTQB-1 4DTQB-1

4I1

4C2

4C1

4I1

4B

4I2

4B

4C2

4C1

4I1

4I2

4B

4C1

4C2

4I1

4I2

4W1

4W1

4W1

4W1

4W1

4W1

4W1

4W1

4W1

4W1

N1

R2

R2

N1

Page 34: Design of 400-220kV Substation

Lighting Design

Adequate lighting is necessary for safety of working personnel and O&M activities

Recommended value of Illumination level Control & Relay panel area - 350 Lux (at floor level) Test laboratory - 300 Lux Battery room - 100 Lux Other indoor area - 150 Lux Switchyard - 50 Lux (main equipment)

- 20 Lux (balance Area / road @ ground level)

Page 35: Design of 400-220kV Substation

Single Bus arrangement

Page 36: Design of 400-220kV Substation

Single Bus System

4. Can be used only where loads can be interrupted or have other supply arrangements.

3. Sectionalizing increases flexibility

3. Bus cannot be extended without completely de-energizing substations

3. Simple Protection

2. Not used for large substations.

2. Difficult to do any maintenance

2. Simple to Operate

1. Used for distribution substations upto 33kV

1. Fault of bus or any circuit breaker results in shut-down of entire substation

1. Low cost

RemarksDemeritsMerits

Page 37: Design of 400-220kV Substation

Main & Transfer Bus

Page 38: Design of 400-220kV Substation

Main & transfer busbar system

3. Fault of bus or any circuit breaker results in shutdown of entire substation.

3. Potential devices may be used on the main bus

. 2. Switching is somewhat complex when maintaining a breaker

2. Any breaker can be taken out of service for maintenance.

1. Used for 110kV substations where cost of duplicate bus bar system is not justified

1. Requires one extra breaker coupler

1. Low initial & ultimate cost

RemarksDemeritsMerits

Page 39: Design of 400-220kV Substation

Double Busbar arrangement

Page 40: Design of 400-220kV Substation

Double Bus Bar Single Breaker system

5. Bus couplers failure takes entire substation out of service.

4. Line breaker failure takes all circuits connected to the bus out of service.

3. High exposure to bus fault.

2. Bus protection scheme may cause loss of substation when it operates.

2. Half of the feeders connected to each bus

1. Most widely used for 66kV, 132kv, 220kV and important 11kv, 6.6kV, 3.3kV substations.

1. Extra bus-coupler circuit breaker necessary.

1. High flexibility

RemarksDemeritsMerits

Page 41: Design of 400-220kV Substation

Double Busbar with Double breaker

Page 42: Design of 400-220kV Substation

Double Bus Bar Double Breaker system

4. High reliability

3. Any breaker can be taken out of service for maintenance.

2. Used only for very important, high power, EHV substations.

2. Would lose half of the circuits for breaker fault if circuits are not connected to both the buses.

2. Has flexibility in permitting feeder circuits to be connected to any bus

1. Not used for usual EHV substations due to high cost.

1. Most expensive1. Each has two associated breakers

RemarksDemeritsMerits

Page 43: Design of 400-220kV Substation

Double main & transfer

Page 44: Design of 400-220kV Substation

Double main bus & transfer bus system

7. Bus fault does not remove any feeder from the service

6. Either main bus can be taken out of service at any time for maintenance.

5. Simple operation, no isolator switching required

4. All switching done with breakers

3. Breaker failure on bus side breaker removes only one ckt. From service

2. Highly reliable

1. Preferred by some utilities for 400kV and 220kV important substations.

1. High cost due to three buses

1. Most flexible in operation

RemarksDemeritsMerits

Page 45: Design of 400-220kV Substation

One & half breaker scheme

Page 46: Design of 400-220kV Substation

One & half breaker scheme

6. Selective tripping

5. All switching by breaker.

4. Each circuit fed by two breakers.

3. Requires 1 1/2 breaker per feeder.

2. Preferred.2. Protection and auto-reclosing more complex since middle breaker must be responsive to both associated circuits.

2. Any breaker can be removed from maintenance without interruption of load.

1. Used for 400kV & 220kV substations.

1. One and half breakers per circuit, hence higher cost

1. Flexible operation for breaker maintenance

RemarksDemeritsMerits

Page 47: Design of 400-220kV Substation

Ring Bus

Page 48: Design of 400-220kV Substation

Mesh (Ring) busbar system

4. Breaker failure during fault on one circuit causes loss of additional circuit because of breaker failure.

3. Requires VT’s on all circuits because there is no definite voltage reference point.

These VT’s may be required in all cases for synchronizing live line or voltage indication

2.Auto-reclosing and protection complex.

1. Most widely used for very large power stations having large no. of incoming and outgoing lines and high power transfer.

1. If fault occurs during bus maintenance, ring gets separated into two sections.

1. Busbars gave some operational flexibility

RemarksDemeritsMerits

Page 49: Design of 400-220kV Substation

Minimum Clearances

4300 mm6400 mm3. Sectional clearance

2100 mm4200 mm

(Rod-conductor configuration)

4000 mm

(Conductor-conductor configuration)

2. Phase to phase

2100 mm3500 mm1. Phase to Earth

220kV400kV

Page 50: Design of 400-220kV Substation
Page 51: Design of 400-220kV Substation
Page 52: Design of 400-220kV Substation

Clearance Diagram

Page 53: Design of 400-220kV Substation

Bus Bar Design

Continuous current rating. Ampacity caculation as per IEEE:738

Short time current rating (40kA for 1 Sec.) IEC-865

Stresses in Tubular Busbar

Natural frequency of Tubular Busbar

Deflection of Tube

Cantilever strength of Post Insulator

Aeolian Vibrations

Page 54: Design of 400-220kV Substation

Gantry Structure Design

ClearancesNo windMax.

(ACSR 750C/ AAAC 850C)

5.

T <= 70% of UTS100%Every Day4.

T <= 22% of UTSNo windEvery Day3.

36%Min.2.

No windMin.1.

LimitsWind PressureTempSr.

Sag / Tension calculation : as per IS: 802 1995

Page 55: Design of 400-220kV Substation

Contd..

Short Circuit Forces calculation

As per IEC : 865

Short circuit forces during short circuit

Short circuit forces after short circuit

Short circuit forces due to “Pinch” effect for Bundled conductor

Spacer span calculation

Factor of safety of 2.0 under normal condition and 1.5 under short circuit condition

Page 56: Design of 400-220kV Substation

spacers

Page 57: Design of 400-220kV Substation

Spacer span Vs Short Ckt. forces

GRAPH OF SPACER SPAN Vs CONDUCTOR TENSION FOR 400 KV TWIN MOOSE ACSR CONDUCTOR

0.00

2000.00

4000.00

6000.00

8000.00

10000.00

12000.00

0 2 4 6 8 10 12 14

SPACER SPAN IN MTRS.

CO

ND

UC

TO

R T

EN

SIO

N P

ER

PH

AS

E I

N K

G.

Page 58: Design of 400-220kV Substation

Earthing Design

Guiding standards – IEEE 80, IS:3043, CBIP-223. 400kV & 220kV system are designed for 40kA. Basic Objectives:

Step potential within tolerable Touch Potential limit Ground Resistance Adequacy of Ground conductor for fault current

(considering corrosion)

Page 59: Design of 400-220kV Substation

Touch and step potential

Page 60: Design of 400-220kV Substation

Lightning Protection – Ground Wire

FIG-4bFIG-4a

Page 61: Design of 400-220kV Substation

Lightning Protection – Lightning Mast

Page 62: Design of 400-220kV Substation