TURBINE SHUTDOWN ACTIVITIES

STOPPING OF BOILER FEED PUMPS

1. ONE BOILER FEED PUMP CAN BE STOPPED IMMEDIATELY AFTER BOILER TRIP.

2. NEXT FEED PUMP CAN BE STOPPED WITHIN ONE HOUR AFTER GETTING CLEARANCE

FROM BOILER. IF BFPS TRIP IMMEDIATELY AFTER TRIPPING OF BOILER DUE TO SUCTION

PRESSURE VERY LOW THEY NEED NOT BE RESTARTED. THEY SHOULD BE STARTED IF

BOILER REQUIRES FEEDING. DEAERATOR LEVEL AND PRESSURE SHOULD BE ENSURED

BEFORE STARTING THE BFP.

3. MS TEMPERATURE BEFORE HP BP SHOULD BE LESS THAN 350O C BEFORE STOPPING BFP

DURING BOILER FORCED COOLING.

STOPPING OF CWPS

1. BALL COLLECTION SHOULD BE DONE 30 MINUTES BEFORE SHUT DOWN.

2. FIRST CWP CAN BE STOPPED IMMEDIATELY AFTER TRIPPING/SHUT DOWN- 30

MINUTES-AFTER BALL COLLECTION.

3. BEFORE STOPPING SECOND CWP LUB OIL COOLERS SHOULD BE CHANGED OVER TO

SERVICE WATER AFTER CLOSING INLET AND OUTLET VALVES TO PREVENT DRAINING OF

COOLERS.

4. SECOND CWP CAN BE STOPPED ONLY AFTER DIVERTING ACW WATER TO COMPRESSORS

FROM RUNNING UNIT OR STOPPING OF RUNNING COMPRESSOR. THIS MUST BE ENSURED

FROM BOILER PM OR BOILER AUX-ADJ. ACW TANK LEVEL TO BE MONITORED DURING

CHANGE OVER.

5. LUB OIL TEMPERATURES SHOULD BE MONITORED AFTER STOPPING CWP.

STOPPING OF ACW PUMPS

1. ACW PUMPS CAN BE STOPPED AFTER STOPPING BOTH CWP AND AFTER DIVERTING ACW

WATER TO COMPRESSORS FROM RUNNING UNIT. THIS MUST BE ENSURED FROM BOILER

PM OR BOILER AUX-ADJ. (ACW PUMPS ARE NECESSARY ONLY FOR COOLING

COMPRESSORS IN BOILERS OTHERWISE ACW BOOSTER PUMP IS SUFFICIENT)

2. ACW PUMPS CAN BE STOPPED IF COMPRESSORS ARE STOPPED IN THE SHUT DOWN UNIT.

IF BEARING TEMPERATURES RISE IS OBSERVED THEN ACW DRAIN IN THE HOT RETURN

LINE (FROM COMPRESSOR LINE) SHOULD BE OPENED (WITH ACW PUMP RUNNING), AS

THERE IS NO COOLING WATER SOURCE FOR ACW.

3. (ACW TEMP SHOULD BE MAINTAINED LESS THAN 38O C)

STOPPING OF ACW BOOSTER PUMPS

1. ACW BOOSTER PUMP CAN BE STOPPED IMMEDIATELY AFTER TRIPPING/SHUT DOWN.

2. ACW BOOSTER PUMP CAN BE RESTARTED AFTER STOPPING CWPS AND ACWPS FOR

COOLING THE BEARINGS OF THE RUNNING EQUIPMENTS LIKE RAPH, FANS, ETC

STOPPING OF CEPS

1. CEPS CAN BE STOPPED AFTER 4 TO 5 HOURS OF SHUTDOWN (ONE HOUR AFTER VACUUM

KILLING)

2. BEFORE STOPPING CEP LP SPRAY WATER INJECTION AND LP B/P V1 AND V3 MAY BE

OPENED TO REDUCE LP EXHAUST HOOD TEMPERATURE.

3. CEPS SHOULD BE STOPPED ONLY AFTER ENSURING THAT LP EXHAUST HOOD TEMP IS

LESS THAN 60 DEGREES WITH LP SPRAY WATER INJECTION AND LP BYPASS SPRAY

VALVES V1 AND V3 IN CLOSED CONDITION.

4. AFTER STOPPING CEPS CD-64. CD-66, DM-6 BGVS. , PUMP SEALING AND VALVE SEALING

VALVES, BFP-WARM UP GATE VALVES SHOULD BE CLOSED. CLOSE DM-23 BGV TO

PREVENT OVERFLOWING AND PUT DM-23 IN MANUAL MODE IN UCB.

5. THESE ISOLATIONS WILL ARREST THE LEVEL RISE IN CONDENSER.

VACUUM KILLING

1. VACUUM CAN BE KILLED IN A SHUT DOWN UNIT PROVIDED THERE IS NO PASSING OF

STEAM INTO TURBINE. THERE SHOULD NOT BE ANY RISE IN SPEED OF BARRING GEAR.

2. IF POSSIBLE CLOSE BOILER STOP VALVES.

3. RE HEATER LINES TO BE EVACUATED COMPLETELY USING LP BP VALVES (HP BP WARM

UP GATE VALVES CAN ALSO BE CLOSED TO PREVENT CRH LINE CHARGING)

4. HP BP WARM UP GATE VALVES CAN BE CLOSED.

5. BEFORE KILLING VACUUM CLOSE BFP WARM UP GVS, HR-15, 16,CR-11, 12 GVS, AST TO

DEAERATOR ROOT VALVE AND PEGGING STEAM VALVE (FIRST CLOSE THE ROOT VALVE

AND THEN PEGGING STEAM VALVE). PRE HEATING DRAIN VALVE AT 19.5 ML HAS TO BE

OPENED PARTIALLY.

6. CLOSE EJECTOR DRAIN TO FLASH BOX.

7. SM 20 TO BE OPENED TO KILL DEAERATOR PRESSURE. CLOSE AS 10 AND EX15. THESE

ISOLATIONS ARE NECESSARY TO ARREST PASSING OF STEAM TO TURBINE.

8. KEEP VACUUM BREAKER VALVE IN OPEN CONDITION ALWAYS IN A SHUT DOWN UNIT.

9. KEEP THE STEAM AND AIR VALVES IN STARTING EJECTOR OPEN ALWAYS IN SHUT DOWN

UNIT.

OPENING AND CLOSING OF DRAINS

THE FOLLOWING VALVES SHOULD BE OPENED IMMEDIATELY AFTER GETTING CLEARANCE FOR

LIGHT UP

1. HP B/P ATMOSPHERIC DRAINS, MS-25,26-HR-47,48 CR-51,52 AND THEIR GVS ,MAL

VALVES AND THEIR GVS,

2. EJECTOR ATMOSPHERIC DRAINS; HPH-5 AND 6 DRAIN CONDENSATE ATMOSPHERIC

DRAINS, AST TO SEALS ATMOSPHERIC DRAIN.

MULSIFYRE COMPRESSORS

1. TWO MULSIFYRE COMPRESSORS ARE IN 0-ML NEAR A ROW-JUST BELOW UNIT-5 BFP-5C

2. COMPRESSED AIR IS USED IN MULSIFYRE SYSTEM-MOT ROOM, OIL CANAL, AND

TRANSFORMERS.

3. THESE COMPRESSORS OPERATE BETWEEN 2.5 TO 3KSC.

4. IF PRESSURE IS <2.5 KSC COMPRESSOR STARTS

5. IF PRESSURE IS >3.0 KSC COMPRESSOR STOPS

6. IF PRESSURE IS <2.0 KSC RESERVE COMPRESSOR STARTS

7. IF PRESSURE IS 1.5 KSC PRESSURE LOW ANNUNCIATION APPEARS IN UCB 4.

8. AT.0.8 KSC THE SYSTEM STARTS OPERATING AND SPRAY VALVES OPEN.

9. IF THERE IS ANY FAULT IN THESE COMPRESSORS THE FOLLOWING ANNUNCIATIONS

WILL APPEAR IN UCB-4.

“MULSIFYRE COMPRESSORS SWITCHGEAR TROUBLE”

“MULSIFYRE PRESSURE LOW”.

1. IF ANNUNCIATIONS APPEAR IN UCB-4 INFORM UNIT-5 AND UNIT-6 GENERATOR BOARD

/ELECTRICAL PM/TURBINE PM IMMEDIATELY TO ATTEND THE FAULT BECAUSE IF SPRAY

VALVES OPEN THEY DISTURB THE MOT LEVEL MONITORS AND CREATE UNNECESSARY

TRIPPING OF THE UNIT.

2. THE POWER SUPPLY FOR THESE COMPRESSORS IS AVAILABLE IN UNITS-5 AND 6 IN EMCC

3. AT LOCAL PANEL IF GREEN LIGHT GLOWS MULSIFYRE COMPRESSOR IS RUNNING IF RED

LAMP GLOWS THEN POWER SUPPLY IS AVAILABLE COMPRESSOR IS NOT

RUNNING/RESERVE.

4. IF BOTH INDICATIONS ARE NOT AVAILABLE IT MEANS THAT POWER SUPPLY IS NOT

AVAILABLE.

5. SYSTEM PRESSURE HAS TO BE CHECKED PERIODICALLY IN THE LOCAL GAUGE.

OVERSPEED TESTING

1. WHILE CARRYING OUT OVER SPEED OIL INJECTION TEST AT LOCAL (ONCE IN A MONTH),

OVER SPEED HYDRAULIC PROTECTION WILL NOT ACT DURING ACTUAL OVER SPEEDING.

HENCE BOARD ENGINEER HAS TO BE MORE CAUTIOUS TO TRIP THE TURBINE IN CASE OF

TURBINE OVER SPEEDING.