Protections Matrix

LUBE OIL SYSTEM

Low Lube oil pressure trip

1. Operation of any two of three pressure switches [63QA-1 (3.44 bar), 63QT-2A (0.55 bar), 63QT-2B (0.55 bar)] when communicator link is in service. 2. Operation of pressure switch 63QT2A (0.55 bar) when failure of communicator link already exist.

TRIP

Failure of main lube oil pump. Leakage from lube oil system. Lube oil filters are choked. Low level of lube oil tank. Fault in pressure regulating valve VPR-2. Wrong operation of pressure switch.

Ensure DC lube oil pump cuts in. Call I&C and mechanical sections and check the system. 0.62 ± 0.03 INCR - CLOSE 0.55 ± 0.02 DEC - OPEN NORMAL = NO

Lube oil header temp high trip

1. Operation of any two of three temperature switches [26QA-1 (74°C), 26QT1A (80°C), 26QT-1B (80°C)] with communicator link in service and speed ≥10% (14HM). 2. Operation of temperature switch 26QT-1A (80°C) when failure of communicator link already exist and speed is ≥10% (14HM).

TRIP

GT cooling water system or Lube oil temperature regulating valve VTR-1 is not working properly. 26QT-1A&1B = 80 ± 2.7°C↑(NC).

Check for proper operation of GT cooling water system. Call I&C section to check VTR-1 and temperature switch.

TRIP

Lube oil header temp high trip

1. Operation of any two of three temperature switches [26QA-1 (74°C), 26QT-1A (80°C), 26QT-1B (80°C)] with communicator link in service and speed ≥10% (14HM). 2. Operation of temperature switch 26QT-1A (80°C) when failure of communicator link already exist and speed is ≥10% (14HM).

Lube oil header temp high trip

1. Operation of any two of three temperature switches [26QA-1 (74°C), 26QT-1A (80°C), 26QT-1B (80°C)] with communicator link in service and speed ≥10% (14HM). 2. Operation of temperature switch 26QT-1A (80°C) when failure of communicator link already exist and speed is ≥10% (14HM).

GT cooling water system or Lube oil temperatur e regulating valve VTR1 is not working properly. 26QT1A&1B = 80 ± 2.7°C↑(NC).

HYDRAULIC OIL SYSTEM

Liquid fuel hydraulic trip pressure low

With 15 seconds time delay when liquid fuel stop valve open signal initiates but 2 out of 3 pressure switches 63HL-1, 2, 3 are still sensing low pressure (1.38 bar).

Post ignition trip of GT

Low oil pressure in liquid fuel hydraulic oil trip circuit. Normal value is 4.5 bar. 1.65 ± 0.14 INCR-CLOSE 1.38 ± 0.06 DEC- OPEN NORMAL = NO

Check control oil filter and its piping. This alarm actuates if the turbine is tripped with the manual emergency trip valve on the turbine or a large leak were to occur in the hydraulic trip circuit piping.

Check for proper operation of GT cooling water system. Call I&C section to check VTR-1 and temperature switch.

FUEL GAS SYSTEM Gas fuel temperature low trip

Inlet gas temperature dropped to 10°C at gas skid sensed by temperature switch 26GL (EKA20CT005). 10 C DEC NORMAL= NC

Start-up fuel flow excessive trip

Excess fuel during startup (1) HSD flow is 1.58 Kg/sec (5.688 T/h) before 40% speed and before turbine warmup time is completed. This is not true during heavy purge. (2) Gas flow is 28.6% FSGR before flame establishes.

Gas scrubber condensate level very high Trip

740 mm level of condensate in gas scrubber sensed by level switch 71GHH.

GT TRIP

Inlet gas temperature is low and the unit trips. Maximum temperature is 65°C and minimum is 15°C.

Check the gas skid local temperature. Vent gas line after shut off valve. Check aux steam boiler for gas heating is in service. Call I&C people to check temperature switch 26GL.

M/C will trip during start sequence.

Excessive fuel for start-up has been detected. For gas fuel the gas control valve is open too far.

Call I&C people to check the servo and feed back signals for proper operation. With liquid fuel: check tripping set point and fuel loop system operation. With gas fuel : check setting value of L.V.D.T. when valve is closed and the calibration of the V.S.R.

GT TRIP when running on gas fuel

Wrong signal from level switch or fault in level controller.

Locally check the condensate level in gas scrubber and drain it. Call I&C people to check the proper operation of level switch 71GHH (EKA20 CL208) and condensate level controller.

Gas Leak Detection System GTShutdown

Shut-off valve manually closed trip

GT shutdown

Gas leakage in turbine and accessory compartments.

Tripping of GT if running on gas fuel.

Following an emergency stop, Find the cause of this action. the operator has manually closed the shutoff valve of the gas circuit.

M/C will not take start on liquid fuel. M/C will take auto shutdown if it is running on FO.

Supply failure of ADP.

Check for gas leakage in turbine and accessory compartments.

At 25% of LEL in case both of the channels operate.

Gas fuel shutoff valve at gas skid is closed from emergency stop push button in CCR-II.

FUEL OIL SYSTEM

Additive dosing panel off

Supply of ADP is off sensed by under-voltage relay 27FS.

Check supply breaker of ADP and call electrical people to attend the fault.

Low liquid fuel pressure trip

Liquid fuel pressure low (2.41 ±0.14 bar) before liquid fuel stop valve sensed by pressure switch 63FL-2.

GT trips with 5 sec delay.

Inlet liquid fuel pressure is too low or the pressure switch 63FL-2 is faulty. 2.75 ± 0.14 INCR-CLOSE 2.41 ± 0.14 DEC- OPEN NORMAL = NO

Check liquid fuel (FO/HSD) supply equipment i.e., filter and fuel oil pumps. Check pressure switch 63 FL-2 and the electronic circuit. Normal value is 6.3 bar.

GT tripped during start sequence. GT TRIP

Failure of cranking motor to start

Check indications on CB of starting motor and call Electrical people to check the fault.

Alarm M/C will not take start if alarm persist.

Compressor bleed valves have not operated properly. They are in wrong position or took an excessive amount of time to move from one position to another.

MISCELLANEOUS Starting device trip

Tripping of starting motor during start before 40% speed.

NormalEmergency supply changeover trip

1 second after stand-by 380V supply CB 52S is closed.

Compressor bleed valve position trouble

1. 11 seconds after speed is > 95% but any of 4 bleed valves limit switches 33CB-1,2,3,4 is sending open status of bleed valve. 2. 11 seconds after speed is < 95% but any of 4 bleed valves limit switches 33CB-1,2,3,4 is sending close status of bleed valve.

Trouble on the normal Check the change over system emergency supply changeover (breakers, electrical circuit) and the power plant electrical supply. Investigate problem. The problem should be corrected before restarting. The master reset switch must be pressed before restarting. Check proper operation of solenoid valve 20 CB: check control air supply of VA 2-1, 2-2, 2-3, 2-4 valves and opening of isolating valve, and cleanliness of air separator.

Chamber flamed out during shutdown

Loss of flame trip

Flame-out on any one of four flame detectors 28FD-1,2,3,4 1) before 35% speed during shutdown or 2) before 5 minutes after desynch of M/C

GT TRIP

Chamber flamed out during shutdown

Check the fuel supply and the fuel control. Check fuel nozzles.

GT TRIP

No signal from three flame detectors.

GT TRIP

Faulty spark plugs. Faulty flame detectors. Low fuel supply than required.

GT TRIP

Faulty thermocouples, gas path parts or uneven distribution of fuel to the nozzles.

Check for the following: fuel being supplied to combustors, flame in all chambers, damaged crossfire tubes, or combustors. Check for proper control valve position and fuel pressure. Check for proper operation of the flame detectors 28 FD-3, 4, 5, 11. Check spark plug current during firing time. Check fuel supply (FQPR or FSG/FSGR). Check if isolating valves on flame detectors are open. Call I&C and electrical people to attend the fault. Analyze data for trends. Perform bore-scope or combustion inspection. Check flow divider, fuel pressures. Check for plugged nozzles.

Flame-out on any three of four flame detectors 28FD-1,2,3,4 when speed is >95%.

Failure to ignite

Failure to fire within one minute firing period

High exhaust temp spread trip

9 seconds after 1) Spread-1> TTXSPL and Spread-2 > 0.8(TTXSPL) and The lowest and 2nd lowest value thermocouples are adjacent. 2) Spread-1 >5(TTXSPL) and Spread-2 > 0.8(TTXSPL) and 2nd & 3rd lowest value thermocouples are

adjacent. 3) Spread-3 > 0.8 (TTXSPL)

Exhaust overtemperature trip Exhaust thermocouple open trip

High vibration trip or shut down

Electrical over-speed trip

1) Temperature control feedback TTXM > 615°C 2) TTXM > Temperature control reference bias TTRXB+65°C. TT-DX-1 to 24 exhaust temperature median corrected by average TTXM is < 121 °C after 50% speed. After 0.5 seconds delay when GT is running and 1. If all vibration sensors of GT (BB-1~5) are disabled or faulty. 2. If all vibration sensors of Generator (BB-7~9) are disabled or faulty. 3. Combination of one alarm and one trip signal. 4. Any trip signal when 2 sensors inputs are disabled. Turbine speed is > 110% of designed speed (3300 rpm).

GT TRIP

Check temp control loop and fuel control system.

GT TRIP

Excessive number of thermocouples not connected

Inform I&C section.

GT TRIP

High vibration due to bowed rotor, mechanical imbalance, bearing failure, etc.

Inform mechanical section to investigate the cause of high vibration and I&C section to check the vibration pickups.

GT TRIP

Speed control system has not limited turbine speed within the trip limits or the turbine trips during the electrical

Electronic over-speed protection is provided by comparison of actual shaft speed to the electronic overspeed set point. Reset the indication

Over-speed bolt trip

over-speed test

from Master Reset before giving next start.

GT TRIP

Electrical over-speed protection has failed to operate and Trip circuit has been tripped by mechanical over-speed action

GT TRIP

Microprocessor self checking program has uncovered a control panel problem. Communication amongst communicator and controllers R, S ,and T has failed or a HCMA card has failed After initiation of fast opening command due to boiler tripping, BYD did not open and BID did not close within 50 seconds. (1) After initiation of fast opening command due to boiler tripping, BYD did not open and BID did not close within 50 seconds. (2) Exhaust duct pressure switch has sensed a high pressure in duct.

Check electrical over-speed system. Check proper operation and setting of over-speed bolt assembly. Repair before starting and reset manually the mechanical over-speed limit switch on the over-speed bolt. Investigate problem. Check section running lights on auxiliary display. Check HCMA card status “OK” lights.

Operation of mechanical over-speed bolt at 112.5% of rated full speed (3375 rpm).

Control system self check trip

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Bypass damper failure to open Trip

After boiler tripping, dampers have failed to change their state within 50 seconds.

Boiler emergency Trip

Failure of boiler dampers to change their state within 50 seconds. Operation of duct pressure high pressure switch.

GT TRIP

GT TRIP

Note indication on dampers control panel and inform STG operator to take the necessary action. Note indication on dampers control panel and inform STG operator to take the necessary action.

Fire-Turbine Hall

GT TRIP

Fire is detected in the turbine hall.

GT tripping + CO2 release

A fire is detected in the load tunnel area. Relays L20FSX and L20PSX are de-energized.

GT tripping + CO2 release

Fire is detected in turbine, accessory, or load coupling area.

Operation of fire detector in turbine hall 45HALL (From panel CWA-01-A01)

Fire ( load tunnel)

Operation of Fire detectors 45FT-8A,8B (510°C)

FireTurbineAccessoryZone 1

Operation of any of following Fire detectors: 1. Accessory compartment: 45FA1A,2A OR 45FA-1B,2B (315°C) 2. Turbine compartment: 45FT1A,2A,3A OR 45FT2A,2B,3B (315°C) 3. Load compartment: 45FT-9A,9B (315°C)

Action The unit should not be operated until the cause has been determined and corrected and the fire protection has been reestablished in its normal condition (refilling of CO2 cylinders, circuit reset, etc). Check for the causes of this trip; hot air or oil or fuel leaks, or short-circuit. Don’t enter the area in which CO2 is released until getting clearance of atmosphere from chemical section. Check if there is really a fire. If it so, ensure fire protection is operated and the doors and dampers are closed; CO2 is released. Do not start the unit if fire detectors are not in service. Check if there is really a fire. If it so, ensure fire protection is operated and the doors and dampers are closed; CO2 is released. Do not start the unit if fire detectors are not in service.

GENERATOR 45 FG-1 = 135C ±

Fire (Generator)

Remote emergency stop

GT TRIP

Fire is detected in generator area.

Check if there is really a fire? If it is, check if the fire protection is actuated and the doors and dampers are closed. If no fire, determine the real cause; fire detector or over-temperature. Note: the unit should not be operated until the problem has been corrected and the fire protection has been re-established in its normal condition.

GT TRIP

M/C is tripped from central control room.

Determine the cause of tripping.

2.8 C NORMAL= NC Adjusted value = 115 C INC 45FG-2 = 120C ± 2 C NORMAL= NO Adjusted value = 114.5 C INC 26G1 (Generator Hot air alarm) = 105C ± 1 C NORMAL= NO 26G2 = (Heater ON/OFF) = 24C ± 1 C NORMAL= NO TRIP order from CCR-II

Generator stator-exciter temperature high

For generator stator winding temperature: 49 G1,2,3 (points # 4,5,6) Alarm 130°C Shutdown 140°C For exciter temperature: Generator Exciter Hot air Temp High Alarm = 90°C Generator Exciter Hot air temp high Trip = 105°C Generator Exciter Cold air Temp High Alarm = 70°C Generator Exciter Cold air temp high Trip = 85°C

Tripping of generator and normal shut down of GT.

Generator stator temperature is excessive caused by lack of cooling or overload. 2 Nos. hot air thermocouples and 0ne cold air thermocouple is used to initiate alarm from any one of three thermocouples, while two out of three logic is developed to initiate trip. GT generator breaker and Exciter breaker will trip and normal shutdown of gas turbine will initiate.

The generator should not be operated when the stator temp is excessive. Check cooling system, reduce overload on generator. Check proper operation of temp detector system and its alarm set point. Check the thermocouple circuit and the ac power of this equipment. Follwing indications will appear on Generator protection panel: L21 Lamp Generator /Exciter temperature abnormal (1st step) L22 Lamp Generator stator / Exciter temperature high (2nd step) L23 Lamp Rupture of Generator /Exciter thermocouple