Dadri stage-1 Reserve Shut down Procedure

 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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