PROTECTION: PROVIDED TO PREVENT DAMAGE TO THE TURBINE RESULTING FROM ABNORMAL OPERATING CONDITIONS. MAIN CRITICAL PARAMETERS FOR THE GAS TURBINE ARE SPEED, TEMP , VIBRATION AND FLAME. LOSS OF FLAME - ACTIVATED IF FLAME NOT ESTABLISHED DURING STARTUP OR FLAME LOST DURING OPERATION. - UV TYPE HONEYWELL MAKE (360 V) - 4 ARE USED (8 CAN BE USED WITH MKV) - 3 OUT OF 4 VOTING FOR FLAME OFF - 64 Hz ON / 32 Hz OFF ( NORMAL FLAME => 250-350 Hz ) - ONLINE SENSOR (FLAME FAILURE) TESTING BY ISOLATION VALVE VIBRATION - ACTIVATED WHEN TURBINE VIBRATION LEVEL REACHES TO ABNORMAL AMPLITUDE. - SEISMIC TYPE SENSORS - 7 SENSORS (12 CAN BE USED) - 2 OUT OF 2 LOGIC - GROUPING IS PROGRAMMABLE - TRANSDUCER SENSITIVITY 0.15 V PEAK/IPS (PROGRAMMBLE FOR 0.05 TO 0.4 V PEAK IN MKV) - FAULT DETECTION FOR OPN. CKT IS POSSIBLE EXHAUST TEMPERATURE - PROTECT THE M/C AGAINST POSSIBLE DAMAGE CAUSED BY OVER FIRING. - AS COMBUSTOR TEMP IS VERY HIGH (1100 DEGC) , IT IS BACK CALCULATED USING CPD AND EX TEMP. - PROTECIVE BACKUP SYSTEM, WHICH OPERATES ONLY AFTER FAILURE OF SPEED AND TEMP OVERRIDE LOOPS. - USING K TYPE T/C (TOTAL 18 T/C USED) - EXHAUST OVER TEMP. TRIP - HIGH SPREAD TRIP - THERMOCOUPLE OPEN TRIP - COMBUSTION MONITOR CAN INDICATE: LINER, TRANSITION PIECE FAILED, COLLAPCE LINER OR HOT CROSS FIRE TUBES. FUEL SYSTEM - BREAK IN FUEL LINE, PLUGGED / STUCK CHECK VALVE, FLOW DIVIDER PROBLEM, ATOM AIR CKT, FUEL NOZZLE PROBLEM. PROTECTION
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TTXSPL ALGORITHM USES THE MAX CTDA AND TTXM TO CALCULATE ALLAWABLE SPREAD. TTXSPL = (0.145 TTXC - 0.08 *CTDA +30) DEGF TTXSPL IS INCREASED BY BIAS AT STARTUP, FUEL TRANSFER, LOAD RAISE/ LOWER AND AT HIGH RATE OF FSR CHANGES. - IF COMMUNICATION FAILS THE ONLY TTXSP1 IS CHECKED. OVER SPEED - MECHANICAL SYSTEM (OPERATED BY OVER SPEED BOLT MOUNTED ON ACC GEAR SHAFT , SPRING LOADED ACCENTRICALLY LOCATED ) AT 113% - ELECTRICAL SYSTEM OPERATES AT 110 % OF SPEED. - TWO INDEPENDENT ELEC CKT IN
AND CORE. EXHAUST PRESSURE - 2 OUT OF 3 LOGIC FOR PRESSURE SWITCHES - TO TAKE CARE OF MALOPERATION OF GD AND GFD. ( i.e. EXHUAST GAS PATH BLOCKED BY GD CLOSED TO HRSG AND GFD OPEN.) LUBE OIL PRESSURE/ TEMP. - 2oo3 LOGIC FOR PREVENTING DAMAGE TO BEARING -AND LONG OUTAGE OF MACHINE. - TO TAKE CARE OF PRESSURE REGULATOR FAILURE, LO LINE LEAKAGE, COOLER MALFUNCTION. BEARING TEMP - FOR BRG. PROTECTION AGAINST RUBBING, SEIZING RESULTING IN HIGH TEMPERATURE OF BEARING, RESULTING IN MELTING OF WHITE METAL. CONTROL/TRIP PRESSURE -
2oo3 LOGIC FOR LOW PRESSURE IN TRIP OIL CKT. OF FUEL TRIP VLVS ( LIQ/NG). FIRE PROTECTION LOW FUEL PRESSURE PROTECTION
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- THIS TRIP IS PROVIDED TO PROTECT THE WARREN PUMP FROM VIBRATION AND OVERHEATING. INLET AIR FILTER DP - UNLOADING PROTECTION IS PROVIDED IN CASE OF HIGH INLET FILTER DP - AS A PREVENTIVE ACTION , SO THAT MACHINE DOES NOT GO IN EXH TEMP CONTROL TURBINE COOLING PRESSURE - UNLOADING TAKES PLACE ON LOW COOLING AIR PRESSURE - TO AVOID BUCKLING OF EXHAUST DIFFUSER AND OVERHEATING OF TUBING CASING RESULTING IN HIGH VIBRATION AND DAMAGE TO MACHINE. INLET GUIDE VANE TROUBLE - IF IGV POSITION < 55 DEG IN RUNNING CONDITION : STALLING - IF IGV POSITION < 32 DEG IN RUNNING CONDITION - IF | SP - MV | > 7 DEG : CONTROLLER FAILURE TRIP FROM DRIVEN EQUIPMENT - FOR THE PROTECTION OF THE DRIVEN EQUIPMENT SUCH AS COMPRESSOR, GENERATOR ETC. EXCESSIVE FUEL - DURING START UP ONLY - FUEL FLOW IS > 3 % FOR XX SECONDS
PROTECTION
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