PROCEDURE FOR RESERVE SHUT DOWN OF STAGE-1 UNITS
PREPARATIONS
1. Open the seal steam drain v/v, MAL-81 and ensure the temp. above 230 deg before seal steam controller,
2. Put the oil guns of AB & CD elevation in scavenge.
3. Open the manual isolating v/v of CBD line at 19 M & 3.5 M.
4. Get the reqd. protections bypassed by C&I engr.
5. Close the Aux. PRDS if in service. (Close As-11, AS-12).
6. Close HT hdr isolating valve at Deaerator floor.
7. Inform CHP , AHP & Switchyard c/r regarding shut down plan.
8. Note down the HFO counter reading.
PROCEDURE
1. Open the seal steam bypass v/v and keep the seal steam pr. Controller in auto.
2. Take upper mill-E and subsequently Mill-F, empty the feeders one by one.
3. Keep Mill- B,C,D,E in service.
4. Take Mill-A i/s and empty the feeder.
5. Take oil gun CD/AB in service.
6. Take all feeders in manual.
7. Close the bunker gate of Feeder –E and empty the Feeder (keep feeder rate of Feeder-D more tha 24.5T for
ignition permit of Mill-E).
8. Subsequently close the bunker gates of Feeder-C & B to empty the feeder.
9. Reduce the load as the Boiler pressure falls.
10. Change over the Unit Bus-A&B on station at load of ~ 80-100 MW.
11. After all the feeders and Mills are emptied, open the HP/LP bypass and reduce the load to
40-50 MW.
12. Trip The Turbine from EPB & ensure starting of AOP.
13. Subsequently trip the Boiler from EPB on desk.
14. Purge the Boiler.
15. Stop ID& FD Fans.
16. Close MS-1 & 2 valve and isolate the elect. Supply.
17. Depressurize the MS line by opening the HP/LP bypass valves.
18. Open all vacuums connected MAL & line drains.
19. Open the atmospheric drains of MS line at 8.5 M after line depressurization.
20. Wait for TG to come on barring.
21. Kill the vacuum after closing all vacuum connected drains and ensuring MS & RH line depressurization. Isolate
the seal steam at 0.3 / 200 mm vacuum.
22. Keep the vacuum breaker open.
23. Maintain Drum /Deaerator/hotwell & CST level.
24. Monitor LPT exhaust temp. after killing Vacuum & stop CEP only after Ex. Temp < 50 deg.
25. Follow the shutdown checklist after stopping the Unit.
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