Gas turbine Frame 6 AVR

23-Feb-2009-17:31

al VATECH VATECH

A4

23/02/2009

23/02/2009

VATECH

BOURGEOIS CHRISTOPHE

VATECH

BOURGEOIS CHRISTOPHE

VALIDE EXTERNE

None

O ffi ci

23/02/2009

G

E

FUNCTIONAL SPECIFICATION

A

3573035 GRD E

super user

FUNCTIONAL SPECIFICATION

CUSTOMER:

GE Energy Products France

PROJECT:

Kuraymat

Edition: 23-Feb-09 3573035A_FunctionalSpecification.doc

PE / shy_aoe Page 1 / 10

CONTENTS GENERAL 1.1. CHARACTERISTICS 2. POWER PART 2.1. CHARACTERISTICS 2.2. FUNCTIONS 3. CONTROL PART 3.1. CHARACTERISTICS 3.2. ADDITIONAL CONTROL FUNCTIONS 4. REGULATION PART 4.1. CHARACTERISTICS 5. PROTECTION PART 5.1. CHARACTERISTICS 5.2. SUPPLIES 5.3. TEST FEATURES 5.4. WATCH-DOG AND COLD TESTS 5.5. USER INTERFACE 5.6. FUNCTIONS 1.

Edition: 23-Feb-09 3573035A_FunctionalSpecification.doc

3 3 4 4 4 6 6 6 6 6 8 8 9 9 9 9 9

PE / shy_aoe Page 2 / 10

1. GENERAL The Generator Control Panel (GCP) is used for the control of the generator and turbine for gas unit. It is included in a Turbine Control Compartment (TCC) and it has interface to the governor controller Speedtronic, the MCC, … 1.1. CHARACTERISTICS 1.1.1. Dimensions The equipment has the dimensions: cubicle containing AVR, protection relay, control, and supply of the field of exciter machine width x high x depth = 1200 x 2200 x 800 mm cubicle containing supply of the rotor of main generator width x high x depth = 800 x 2200 x 800 mm 1.1.2. Structure The GCP is freestanding cubicle equipped with necessary lifting facilities. All devices have an easy access for replacement. 1.1.3. Protection Degree The GCP is built for indoor conditions with a protection degree IP31 according IEC Standard 144. 1.1.4. Site Conditions • • • • •

Altitude: Temperature: Humidity: Pollution: Acceleration:

max. 1000 m max. 40°C 80 % no 0,2 g horizontal

1.1.5. Painting • Interior metal surfaces has the painting with two coats of RAL7035 30 µm total • Exterior metal surfaces has the painting with two coats of RAL 7035 70 µm total

1.1.6. Power Supplies Following power supplies are connected to the GCP: • • • • • • •

125 Vdc (1) supply for the regulation, protection, control and sequences 125 Vdc (2) supply for the forcing unit 125 Vdc for unit breaker command channel 1 125 Vdc for unit breaker command channel 2 125 Vdc for line breaker command channel 1 125 Vdc for line breaker command channel 2 230 Vac plug supply

A power supply fault contact of 125 Vdc (1) is given to the SPEEDTRONIC equipment. 1.1.7. Measurements The GCP is connected to measurement transformers with rated secondary circuits of 1 A and 110 V , three phase measuring for CT’s and PT’s. The rated frequency is 50 Hz. Edition: 23-Feb-09 3573035A_FunctionalSpecification.doc

PE / shy_aoe Page 3 / 10

2. POWER PART Generator excitation system is supplied from MCC via a three-phase dry type transformer. The voltage for the supply of the field of the exciter machine is rectified through a three-phase full wave rectifier bridge. Static frequency converter which supplies the stator of the machine during the start up phase of the machine requires current controlled field for the rotor of the main generator. During this period called as SFC start, the current for the rotor of the main generator is rectified by a separate three-phase half wave rectifier bridge. 2.1. CHARACTERISTICS Excitation maximum capability: • • • • • •

Exciter field current, normal operation: Ceiling current: Ceiling time: Excitation supply, normal operation: Rotor excitation current, SFC start up Excitation supply, SFC start up:

20 A 32 A 10 s 280 V / 50 Hz 400 A 90 V

2.2. FUNCTIONS 2.2.1. Starting Condition 2.2.1.1 SFC Mode The static frequency converter is designed to start the gas turbine using the synchronous generator in motor mode. During start up sequence, the SFC energizes the generator terminals with variable voltage and frequency, the machine is acting as asynchronous motor. As soon as the gas turbine reaches its self sustaining speed (84% of rated speed) the SFC is disconnected. The gas turbine accelerates the machine to the rated speed. The SFC Mode can only be enabled in case of opened field breaker with excitation start command coming from SFC. The enabling of SFC Mode switches the thyristor pulses to the SFC starting bridge and brings the down command for the brushes in case of readiness of the excitation, the auxiliaries of the brush control and the SFC. After reaching of the down position for the brushes the sequencer gives the on command for the field breaker on the primary side of the excitation transformer. The contact coming from field breaker allows the enabling of the gate pulses and the rotor current is controlled with a P controller in accordance to the set value coming from SFC. 2.2.1.2 Generator Mode Following conditions must be fulfilled • Field breaker permissive to close command coming from Speedtronic • Field breaker command from Speedtronic, after reaching of the speed limit • No tripping order

In addition to the starting conditions the voltage regulator must be available, so the closing order causes the closing of the field breaker and increase of the stator voltage up to automatic channel set value. 2.2.2. Forcing System The voltage coming from MCC feeds the excitation power circuit. A possible voltage drop during changing over from the MCC supply to the client supply has to be prevented by the forcing circuit, which is activated for a short period. The forcing circuit takes its energy from battery. The forcing is Edition: 23-Feb-09 3573035A_FunctionalSpecification.doc

PE / shy_aoe Page 4 / 10

stopped as soon as the changeover is finished. The forcing is validated only when the excitation breaker is closed and the generator is online. 2.2.3. Unit Breaker Closing The unit breaker closing command is created in the GCP. It is initiated from automatic cahnnel activated by the automatic synchronization, which is implemented in the governor controller. 2.2.4. Unit Breaker Tripping Two separate channels (unit breaker tripping coil 1 &2) realize the unit breaker tripping. The Speedtronic equipment gives the power supply polarities. The tripping can be issued by the Speedtronic, the generator protection system or manually inside the GCP. 2.2.5. Stop The field breaker opening is allowed only if the unit breaker is open to avoid the generator from running under asynchronous mode. With a trip of the excitation system a tripping order is given which opens the unit circuit breaker.

Edition: 23-Feb-09 3573035A_FunctionalSpecification.doc

PE / shy_aoe Page 5 / 10

3. CONTROL PART The control part has following functions: • Logic and analog signals transmittal • Serial link for Modbus communication

3.1. CHARACTERISTICS • • • •

CT’s input: PT’s input: Frequency: Supply voltage:

1A 110 V 50 Hz 125 Vdc

3.1.1. Display and Local Control The display and local control is realized through serial link on the turbine controller HMI. 3.2. ADDITIONAL CONTROL FUNCTIONS • Analog indication instrument for excitation field current and excitation field voltage • 4-20 mA Analogue Signals: for following physical values active power P -11 - 110 MW, reactive power Q -40 -+100 MVAr stator voltage U 0 - 13,8 kV stator current I 0 - 5,5 kA frequency f 45 - 55 Hz power factor p.f. 0,5 lag – 0,2 lead • 4-20 mA Analogue Signal: for excitation voltage for excitation current • Dead bus coupling • Active & reactive energy meter (cl. 0,2)

4. REGULATION PART The regulation part has the function to regulate the generator stator voltage by adjusting its field current. The current controller permanently controls the excitation field current. The regulation system functions are to • • • •

Adjust the generator stator voltage Be active for the stability of energy evacuation to the grid Have a good response time on troubles Keep the generator in its stability area

4.1. CHARACTERISTICS • • • • • • • •

Set point range: Regulation accuracy: Active load compensation: Reactive load compensation: Field current permanent limitation: Ceiling current limitation: Frequency range: Structure of voltage regulator:

Edition: 23-Feb-09 3573035A_FunctionalSpecification.doc

90 % … 110 % of rated voltage better than ±0,5 % 0 … ±20 % 0 … ±20 % 110 % rated field current 160 % rated field current for 5 s 10 … 330 Hz two control loops in master-slave connection master: PID-characteristic (AVR) slave: P(I)-characteristic (field current) PE / shy_aoe Page 6 / 10

4.1.1. Automatic Voltage Regulator The regulator and gate-control unit GMR3 is a multi-processor voltage regulator which comprises a complete voltage regulator with limiters and additional regulators, the firing circuit for single-phase and three-phase operation and the logic control that is necessary for the proper operation of an excitation system. The system comprises 4 processors, digital and analogue in- and outputs, a processing card to convert the actual values of the machine and pre-amplify the gate pulses. 4.1.1.1 Operating Principle The voltage regulator consists of two control-loops in master-slave connection. The master is a voltage regulator and controls the generator voltage dependent on the automatic channel setvalue. It has PID-characteristic with an internal integrator-stage feed back. The slave is a field current regulator with P(I)-characteristic. Due to this double loop structure high control speed and stability at all operation modes and loads will be achieved. The actual values are isolated by matching transformers and prepared for processing by the subprocessors. 4.1.1.2 Scope of Program The software comprises the operating system and the regulator program with the setting parameters for the main processor board and the different sub-programs for the sub-processor boards. The operating system provides input and output conversion, coordinates the sequence of the regulator program, the data exchange to the sub-processors, and enables communication with the regulator via a serial interface. 4.1.1.3 Main features of the microprocessor system • Voltage regulation (master, automatic operation) to an adjustable voltage set value, using a field current loop (slave) • Field current regulation as manual operation • Manual and automatic smooth change-over between automatic and manual operation • Active and reactive load compensation • Load angle limitation • Over fluxing limiter • Stator voltage limitation • Maximum field current limiter (undelayed), to limit the maximum possible short-time ceiling current • Maximum field current limiter with time-delay depending on the over current (inverse time characteristic),to limit the continuous admissible field current • Diode failure supervision • Forcing sequence • Softstart for excitation start-up • Test switch on the gate-control board for tests with open loop regulation circuits • Stator current limitation • Power System Stabilizer (PSS) • Modbus

All facilities for adjustments and settings of the AVR are part of the software. Thus no potentiometers are used. 4.1.2. Field Current Regulator (Manual Operation Mode) For manual operation the current loop of the regulator is used to control the field current dependent on the manual operation set value. The manual set-value is also part of the software and no potentiometer is used. To increase the reliability no limiters are acting in this mode. Edition: 23-Feb-09 3573035A_FunctionalSpecification.doc

PE / shy_aoe Page 7 / 10

4.1.3. Auto Tracking and Transfer between Automatic and Manual Mode A change over from voltage regulator (automatic mode) to field current regulator (manual mode) may be done manually or automatically. If the voltage regulator part fails, control is transferred automatically to the manual mode (failure of the actual generator voltage). The transfer from manual to automatic mode can be done manually only. A follow-up regulator allows the smooth change over from one mode to the other without balancing (no balancing meter needed). If any case of manual operation (field current regulation) the actual set point exceeds the setting range of the AVR; a switch over to automatic mode is blocked. 4.1.4. Operation, Monitoring and Digital Sequencer In the system GMR3 sequencing and monitoring is an integrated part of the software thus having the same reliability as the voltage regulator. For sequencing, monitoring and alarm indication the following features are provided: • Digital sequencer for correct start-up and shut-down procedures of the excitation system, including switching of all necessary contactors • Input, output signal processing (potential-free interface to other systems) • Supervision of excitation, including alarm and/or trip outputs • Operation and monitoring unit for local operation from the excitation panel (excitation ON/OFF; setpoint RAISE/LOWER; pre-selection of operation mode; reset of alarms) with feedback indications • This operation panel consists of a Touch Panel for the indication of status signals and measurement values • All alarms of the excitation system are stored and indicated on the display of the local monitoring unit in the sequence of their occurrence. • Various generator quantities are indicated on the display of the local monitoring unit: ˘ Generator voltage, Generator current ˘ Field current ˘ Active power, Reactive power, Power factor

5. PROTECTION PART The protection part has the function to protect the generating unit composed of: • • • •

turbine generator unit transformer auxiliary transformer

The protection system includes the necessary treatment, interface display and control for the trips and alarms initiation. 5.1. CHARACTERISTICS • • • •

CT’s input: PT’s input: Frequency: Supply voltage:

1A 110 V 50 Hz 125 Vdc

5.1.1. Event & Fault Records Event records are generated whenever there is a protection function operation, energization of a status input, operation of an output relay or any hardware failure. The record consists of the date and time of the fault, the state of inputs, relay outputs and protection functions together with the measurement values during the fault.

Edition: 23-Feb-09 3573035A_FunctionalSpecification.doc

PE / shy_aoe Page 8 / 10

5.1.2. Disturbance Recorder The disturbance recorder can be triggered from selected relay outputs or internal status. They are stored in a non-volatile memory. Necessary software is included for fault analysis.

5.2. SUPPLIES The necessary internal supplies required for the protection need is taken from the available power supply. This supply is protected and monitored.

5.3. TEST FEATURES A dedicated test function is included to allow routine maintenance and fault finding operations. Available tests:

input check output check

logical treatment check The protection relays are designed to allow such tests without initiating any trip. 5.4. WATCH-DOG AND COLD TESTS Cold tests are carried out by the relay when it is energized. These tests include checks on the timer, microprocessor, memory, and inputs. Continuous self-monitoring, in the form of a watchdog, memory checks and analogue input module tests, is performed. In case of a failure, the relay will either lockout or attempts a recovery, depending on the type of failure detected. If a protection minor fault is detected (i.e. the protection may work properly), a signal is sent to a buzzer implemented in the cubicle. If it is a major fault, a tripping signal is given to the system.

5.5. USER INTERFACE A local user-friendly menu permits the access to the protection parameters. A local display shows the set parameters. A remote access user interface is available from a PC. The relay interconnection is possible by RS232 port for remote relay interconnection. A local parallel port is dedicated to the print function. 5.6. FUNCTIONS The protection includes the following functions: • • • • • • • • • • • • • • • • • •

87G, Generator differential 51V, Overcurrent voltage restrained 46G, Negative phase sequence overcurrent 59G, Overvoltage 27G, Undervoltage 81G.U, Under-Frequency 81G.O, Over-Frequency 32G, Reverse power 24G, Overfluxing 40G, Underexcitation 64G95, 95% Stator earth fault 64B, Cable earth fault 78G, Out of step 60VTS, Balance voltage 21G, Under impedance 50BF, Breaker failure 50/27, Inadvertent energization 87B2, 2 branches block differential

Edition: 23-Feb-09 3573035A_FunctionalSpecification.doc

PE / shy_aoe Page 9 / 10

• 64REF, Restricted earth fault • 50/51T, Main transformer overcurrent • Protection redundancy

Edition: 23-Feb-09 3573035A_FunctionalSpecification.doc

PE / shy_aoe Page 10 / 10