Generator Excitation System Desing Consideration

Generator Control System Seminar Hungary 2007 Generator Excitation System Design Consideration Christophe Del Popolo Budapest, Hungary 2007 LIST OF TOPICS A) Type of generators B) What kind of data are needed ? C) Type of power supplies D) Sensing circuits : PTs and CTs LIST OF TOPICS F) Accessories G) New technologies (introduction) * H) Examples and how to read a single line diagram E) Control voltage * Digital technologies / digital products Identify generator type: - Slip ring - Brush type - Brushless type A) TYPE OF GENERATORS SLIP RING GENERATOR F+ F- GENERATOR STATOR SLIP RINGS / BRUSHES REVOLVING FIELD STATIC EXCITATION SYSTEM (or Static Excitation) AVR ROTARY EXCITER, BRUSH-TYPE GENERATOR F+ F- AVR FIELD (STATOR) VOLTAGE REGULATOR ARM SLIP RINGS BRUSHES GENERATOR STATOR Brushless Rotary Exciter F+ F- AVR FIELD STATIONARY ROTATING STATIONARY ROTARY EXCITER GENERATOR Generator data : - APPARENT POWER (in kVA) - GENERATOR OUTPUT VOLTAGE (in Volts / V) - GENERATOR FREQUENCY (in Hertz / Hz) - POWER FACTOR (nominal = 0.8 or 0.9 in general) B) WHAT KIND OF DATA ARE NEEDED ? Different relation ships between generator powers : 1) S = U x I x 3 (apparent power in VA) 2) P = U x I x 3 x cos phi (active power in W) 3) Q = U x I x 3 x sin phi (reactive power in Vars) 4) S = (P + Q) 5) cos phi = P / S 6) tan phi = Q / P B) WHAT KIND OF DATA ARE NEEDED ? Excitation data : 1) At no load (voltage and current) 2) At full load 3) At full load +10% (or +20%) 4) In ceiling condition 5) In short-circuit condition B) WHAT KIND OF DATA ARE NEEDED ? B) WHAT KIND OF DATA ARE NEEDED ? Other values and remarks : 1) Time constant Tdo (to determine the discharge components) 2) Exciter resistance (cold and hot) : difference of 10 or 15% 1) Shunt C) TYPE OF POWER SUPPLY 2) Auxiliary windings 3) PMG (Permanent Magnet Generator) 4) Separate source Power Input from Generator Line (shunt mode) GEN FIELD OUTPUT POWER INPUT SENSING INPUT VOLTAGE ADJUST F+ 3 E1 F- 4 E3 7 CW USE POWER TRANSFORMER IF REQUIRED POWER CIRCUIT SENSING CIRCUIT VOLTAGE REGULATOR A B C N 6 BOOST CIRCUIT NEEDED. Power Input from Auxiliary windings GEN FIELD OUTPUT POWER INPUT SENSING INPUT VOLTAGE ADJUST F+ 3 E1 F- 4 E3 7 CW USE POWER TRANSFORMER IF REQUIRED POWER CIRCUIT SENSING CIRCUIT VOLTAGE REGULATOR A B C 6 BOOST CIRCUIT NOT NEEDED. Power Input from a PMG GEN FIELD OUTPUT POWER INPUT SENSING INPUT VOLTAGE ADJUST F+ 3 E1 F- 4 E3 7 CW POWER CIRCUIT SENSING CIRCUIT VOLTAGE REGULATOR A B C N 6 PMG BOOST CIRCUIT NOT NEEDED. Power Input from a PMG Example of one PMG curveCurrentPMG output voltage (in Vac)++++++++I 0/4 I ceiling I 4/4 (at nominal speed) Power Input from a PMG a)Voltage at no load (maximum voltage) : b)Voltage at ceiling (minimum voltage) : & maximum apparent power (in VA) : c) Rated power in nominal condition (in VA) : d) Frequency : e) Three phase : f) Single phase : Yes / No Yes / No Power Input from a separate source GEN FIELD OUTPUT POWER INPUT SENSING INPUT VOLTAGE ADJUST F+ 3 E1 F- 4 E3 7 CW USE POWER TRANSFORMER IF REQUIRED POWER CIRCUIT SENSING CIRCUIT VOLTAGE REGULATOR A B C N 6 SPEED CONTACTS BOOST CIRCUIT NOT NEEDED. D) SENSING CIRCUITS (PTs and CTs) - To match the AVR characteristics : 1) Sensing voltage transformers : Identify the type Identify how many transformers Identify general characteristics (voltages, frequency, burden, accuracy,) - In addition : D) SENSING CIRCUITS (PTs and CTs) Examples of PTs connections : D) SENSING CIRCUITS (PTs and CTs) - To match the AVR characteristics : 2) Sensing current transformer : Identify the type (ring, wound) Identify general characteristics (voltages, frequency, burden, accuracy,) CT on phase B ? - In addition : D) SENSING CIRCUITS (PTs and CTs) 3) Phase sequence : E1 E2 E3 CT U V W V V W U W W U V U +1 +1 E) CONTROL VOLTAGE - For contactors, relays, AVR, transducers, PLC, lamp 1) Can be AC or DC : - For the field flashing system (if needed) -> size of the battery to be checked - For AC purpose : - For DC purpose : Fuse Fuse Rectifier bridge Fuse Resistor Blocking diode F) ACCESSORIES - Choice has to be made according to : 1) Meters : Generator data (kVA, V, Hz, cos phi) Excitation data (Vdc, Idc) Customer requirements F) ACCESSORIES - Choice has to be made according to : 2) Transducers : Generator data (kVA, V, Hz, cos phi). Excitation data (Vdc, Idc) Customer requirements F) ACCESSORIES 1) PLC (programmable logic controller) : - Communication with other devices (RS485, Profibus, ) * - Communication with internal devices (via RS485, analog output, ) * - Communication : with HMI (Human Machine Interface) * G) NEW TECHNOLOGIES * Digital technologies / digital products MASTER Modbus communications Protection A.V.R. (Transducers) PLC Excitation system+protections Generator Control Panel (GCP) Turbine Control Panel (TCP) Control Room Modbus PLC Modbus - Communication with other devices (RS485, Profibus, ) Speed Governor Protection (Transducers) MASTER Modbus communications Setpoint Control * Metering Status ** PLC Example : A.V.R. : Generator Control Panel (GCP) Control Room Modbus - Communication with internal devices (via RS485, analog output, ) * Raise / Lower : Gen. Voltage : Power Factor/Vars ** Excitation limiting ** Active mode (Auto, Manu, ) - Communication : with HMI (Human Machine Interface) H) INTERESTING INFORMATION ON A SINGLE LINE DIAGRAM 2) Example : eV` `e .l:+e Vl+ - Sensing circuit (current) : * Frequency = 50Hz * (Voltage = 660V) * In / 5A * b phase H) INTERESTING INFORMATION ON A SINGLE LINE DIAGRAM - Power circuit : * Frequency = 50Hz * primary voltage = 660V * Three phase * Single phase - Sensing circuit (voltage) : * Frequency = 50Hz * primary voltage = 660V * Single phase * Rotating diodes (low excitation data) - Generator data : * primary voltage = 660V * Generator frequency = 50Hz - Field flashing circuit : * DC source * Resistor H) INTERESTING INFORMATION ON A SINGLE LINE DIAGRAM * 2 CTs (open-delta) - Boost circuit : * (Voltage = 660V) * Over excitation (76 function) - Protective relays : * Over voltage (59 function) * Under voltage (27 function) * On AC power circuit (boost+PT) - Earth connections : * On DC power circuit ! - Locate the generator 1) Conclusion : - Locate the sensing circuits - Locate the power circuits (which type of power supply ? Boost circuit ?) - Locate the accessories (specific transducers, meters, ) - Is there any mechanical drawing (that could give an idea about the sizes of the components, ) H) INTERESTING INFORMATION ON A SINGLE LINE DIAGRAM In order to check the interface between our equipment and your system, please fill in the following data sheet:Customer :Cotation/order number :Project name :I) Generator data :Power (in kVA) : Voltage (in V) :Frequency (in Hz) :Power f actor :2) Type of system :Mounting plateCubicleSmall cabinet3) Excitation current & voltage :Current VoltageAt no load:At f ull load:In short circuit conditions (if used)4) Forcing condition :Typically 1.6x excitation voltage at f ull load :5) Type of the input power :A. PMGa)Voltage at no load (maximum voltage) :b)Voltage at ceiling (minimum voltage) : & maximum apparent power (in VA) :c) Rated power in nominal condition (in VA) :d) Frequency :e) Three phase :f ) Single phase :B. POWER TRANSFORMEUR (VOLTAGE)a) Voltage on primary side :b) voltage on the secondary side :c) f requency 50Hz:60Hz:d) Rated power in nominal condition (in VA) :e) Three phase :f ) Single phase :C. AUXILIARY WINDINGSa) Voltagesb) f requency 50Hz:60Hz:c) Rated power in nominal condition (in VA) :d) Three phase :e) Single phase :f )D. EXTERNAL SOURCEa) Nominal voltage type (DC or AC)b) Rated power in nominal condition6) CT & PT ratio for the sensing circuit :A. PT RATIOa) Primary voltage :b) Secondary voltage :c) Apparent power (25VA min)d) Three phase :e) Single phase :f ) 2 single phase xf mrconnected in deltaB. CT RATIOa) Primary current :b) secondary current (1 or 5A)1A :5A :c) Burden (in VA) :d) Connected the B-phase :7) Control voltage for the contactors, relays, transducersa) 24Vdc (recommended) :b) 110Vdc :c) 125Vdc :d) Other : 8) Control voltage for the build-up (if used) :a) 24,110 or 125Vdc :b) AC source :c) Other :9) Certifications :a) CE requirements :b) UL requirements :c) Marine requirements (RINA,..) :d) Other :10) Size of the equipment :a) Maximum dimensions of the mounting plate (mm) Height : Width : Thickness : b) Maximum dimensions of the cubicle (mm)Height : Width : Depth :c) Maximum dimensions of the small cabinet (mm)Height : Width : Depth :11) Other specifications :a) Is there any :Vars transducer :Watts transducer :Power f actor transducer :CT Ratio :PT Ratio :Balanced load :Other :b) Other request :QUESTIONS