Generator Excitation System Desing Consideration

Generator Control System Seminar : 

Generator Control System Seminar Hungary 2007

Generator Excitation System Design Consideration : 

Generator Excitation System Design Consideration Christophe Del PopoloBudapest, Hungary2007

LIST OF TOPICS : 

LIST OF TOPICS A) Type of generators B) What kind of data are needed ? C) Type of power supplies D) Sensing circuits : PT’s and CT’s

LIST OF TOPICS : 

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

A) TYPE OF GENERATORS : 

Identify generator type: - Slip ring - Brush type - Brushless type A) TYPE OF GENERATORS

SLIP RING GENERATOR : 

SLIP RING GENERATOR F+ F- GENERATOR STATOR SLIP RINGS / BRUSHES REVOLVING FIELD STATIC EXCITATION SYSTEM (or Static Excitation) AVR

ROTARY EXCITER,BRUSH-TYPE GENERATOR : 

ROTARY EXCITER,BRUSH-TYPE GENERATOR F+ F- AVR FIELD (STATOR) VOLTAGE REGULATOR ARM SLIP RINGS BRUSHES GENERATOR STATOR

Brushless Rotary Exciter : 

Brushless Rotary Exciter F+ F- AVR FIELD STATIONARY ROTATING STATIONARY ROTARY EXCITER GENERATOR

Slide 9: 

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 ?

Slide 10: 

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 = (P² + Q²) 5) cos phi = P / S 6) tan phi = Q / P B) WHAT KIND OF DATA ARE NEEDED ?

Slide 11: 

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 ? : 

B) WHAT KIND OF DATA ARE NEEDED ? Other values and remarks : 1) Time constant T’do (to determine the discharge components) 2) Exciter resistance (cold and hot) : difference of 10 or 15%

C) TYPE OF POWER SUPPLY : 

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) : 

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 : 

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 : 

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 : 

Power Input from a PMG (at nominal speed)

Power Input from a PMG : 

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 : 

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 (PT’s and CT’s) : 

D) SENSING CIRCUITS (PT’s and CT’s) - 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 (PT’s and CT’s) : 

D) SENSING CIRCUITS (PT’s and CT’s) Examples of PT’s connections :

D) SENSING CIRCUITS (PT’s and CT’s) : 

D) SENSING CIRCUITS (PT’s and CT’s) - To match the AVR characteristics : 2) Sensing current transformer : - In addition :

D) SENSING CIRCUITS (PT’s and CT’s) : 

D) SENSING CIRCUITS (PT’s and CT’s) 3) Phase sequence : E1 E2 E3 CT

E) CONTROL VOLTAGE : 

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 :

F) ACCESSORIES : 

F) ACCESSORIES - Choice has to be made according to : 1) Meters :

F) ACCESSORIES : 

F) ACCESSORIES

Slide 27: 

- Choice has to be made according to : 2) Transducers : Generator data (kVA, V, Hz, cos phi). Excitation data (Vdc, Idc) Customer requirements F) ACCESSORIES

G) NEW TECHNOLOGIES : 

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

- Communication with other devices (RS485, Profibus, …) : 

MASTER Modbus communications Excitation system+protections Generator Control Panel (GCP) Turbine Control Panel (TCP) Control Room Modbus Modbus - Communication with other devices (RS485, Profibus, …) Speed Governor Protection (Transducers)

- Communication with internal devices (via RS485, analog output, …) : 

MASTER Modbus communications 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) : 

- Communication : with HMI (Human Machine Interface)

H) INTERESTING INFORMATION ON A SINGLE LINE DIAGRAM : 

H) INTERESTING INFORMATION ON A SINGLE LINE DIAGRAM 2) Example :

H) INTERESTING INFORMATION ON A SINGLE LINE DIAGRAM : 

H) INTERESTING INFORMATION ON A SINGLE LINE DIAGRAM

H) INTERESTING INFORMATION ON A SINGLE LINE DIAGRAM : 

H) INTERESTING INFORMATION ON A SINGLE LINE DIAGRAM

H) INTERESTING INFORMATION ON A SINGLE LINE DIAGRAM : 

- 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

QUESTIONS : 

QUESTIONS