PERMISSIVES
GENERAL
To open Lead HRSG HP, IP, LP, HRH & 1. DD open feed back
CRH steam stop valves
To open Lead HRSG HP, IP, LP, HRH & 1. HP steam stop bypass valve open feedback
CRH steam stop main valve
To open Lag HRSG HP, LP steam stop 2. Upstream temp of the bypass valve will be 5 C more
bypass valve than downstream temp
3. Upstream pressure of the bypass valve will be 2 bar
more than downstream pr
To open Lag HRSG HP, LP steam stop 1. Diff bet the upstream temp of the main valve and
main valve upstream temp of the ST inlet valve less than 50 C.
To open Lag HRSG HRH steam stop GCB close feedback
bypass valve
To open Lag HRSG HRH steam stop HRH steam stop bypass valve open feedback
main valve
GT exh temp set point = HRSG avg Once HRSG avg wall temp reached 371 C
wall temp + 40 C
To open HRH new drain valve 1. HRH main CV psn <2%
2. HRH steam temp <450 C
To close HRH new drain valve 1. HRH main CV psn >2%
2. HRH steam temp >450 C
To open aux steam valve from CRH & 1. CRH pr > 19 bar
close aux steam valve from HP steam 2. ST load > 105 mw
BYPASS STACK DAMPER
To close stack damper, DD be closed
To open stack damper, no need anything
STEAM TURBINE START PERMISSIVES
1. HP steam pressure min = 49.6 bar & Max = 132.9 bar
2. Reheat steam pressure: Optimum = 6.8 bar, Min = 5.1 bar, Max = 11.9 bar.
3. HP steam diff temp: Optimum = 565 C, Min = 510 C, Max = 565 C
4. Reheat steam diff temp: Optimum = 565 C, Min = 510 C, Max = 565 C
5. Sealing steam permissive: Optimum = 371 C, Min = 260 C, Max = 398 C
6. Turbine metal temp [HP/IP]: Must be greater than 23 C
7. Lube oil temp on Turning gear = Must be greater than 23 C
8. Exhaust Pressure: Must be less than 127 mmHg
9. Turbine rotor turning: Actual speed > 0 rpm
10. Eccentricity: Min = 0 mm, Max = 0.1 mm
11. Differential expansion: Min = -6.3 mm, Max = 10 mm
12. DCS permissive status : OK to Roll [DCS permissive to start]
13. Drain valves: All drains open & Healthy [MOVs]
14. Critical instruments healthy: Instruments must be healthy
15. Turbine status: Turbine must be reset
16. Hold status: No active ATS holds on list.
17. Vibration trip: Must be on TG before restart.
18. Earth switch L57GG OK to start: Earth switch L57GG must be open
19. Controller hardware status: All IO packs are communicating & Controllers Heart beat healthy, in
controlling state.
20. Stress stabilization: HP stress stabilized, RH stress stabilized
1000 RPM Permissive
1. Generator breaker open.
2. ST Start permissive satisfied.
3. No Active holds.
3000 RPM Permissive
Generator breaker open.
No active holds.
RATED SPEED PERMISSIVES
1. No active hold.
2. Lube oil temperature ok. >35 C.
MINIMUM LOAD PERMISSIVES
1. Auto synch permitted.
2. At Rated speed for 60 secs.
3. Lube oil temp ok. >37 C.
4. HP flow mode permitted by DCS.
5. HP steam temp ok. Optimum = 565 C, Min = 510 C, Max = 565 C
6. HP steam pressure ok. Min = 49 kg/cm2, Max = 132 kg/cm2.
7. No active holds.
8. Primary over speed test not in progress.
9. Emergency over speed test not in progress.
HP FLOW PERMISSIVES
1. Speed / Load reference ok.
2. IV reference > 50%.
3. HP flow mode permitted by DCS.
4. No active holds.
5. HP steam temperature ok. Min = 510 C, Max = 565 C.
6. HP steam pr ok. Min = 49 kg/cm2, Max = 132 kg/cm2.
LOAD COMMAND PERMISSIVES
1. No active holds.
2. HP in flow mode.
IPC PERMISSIVES
1. No active holds.
2. HP in flow mode.
LP ADM PERMISSIVES
1. Turbine load Ok. > 10%.
2. In HP flow modes.
3. Turbine reset.
4. GCB closed.
TEMPERATURE RAMP PERMISSIVES
1. RH steam - Metal temp ok. RH steam – Metal temp < 83.3 C.
2. HP steam – Metal temp ok. HP steam – Metal temp <83.3 C.
3. HP differential expansion ok.
4. GCB closed.
5. In HP flows mode.
INSTRUMENT HEALTH
1. All HP steam TCs healthy.
2. All HP control start TCs healthy.
3. All HP exhaust TCs healthy.
4. All RH steam TCs healthy.
5. One or More L-1 TCs unhealthy.
6. All HP steam PTs healthy.
7. All RH steam PTs healthy.
8. All first stage PTs healthy.
9. All LP exhaust PTs healthy.
10. All vibration probes healthy.
11. All IP/LP DXD instruments healthy.
12. Thrust bearing axial probes healthy.
13. RH stop valve Pos feedback healthy.
14. All exhaust TCs healthy.
15. All RH vertical joint PTs healthy.
HRSG START PERMISSIVES
1. DD in remote.
2. DD ready.
3. DD Emer open actd.
4. GD CVR close feedback.
5. GD close FB.
6. GD open FB.
7. DD emergency close or FW run back.
8. DD trip FB.
9. GT exhaust temp permissive.
10. Stack damper MOV open FB.
11. GD vent valve close FB.
12. Main FWP group in service.
13. HRH bypass HPU no fault.
14. LP bypass HPU no fault.
15. HP bypass HPU no fault.
16. Stack damper opened.
17. HP drum level not low.
18. IP drum level not low.
19. LP drum level not low.
20. Condensate system in service FB.
21. Temp match ON command or Flame not detected.
22. Any one CPH RC pump running or GT in LF mode.
23. Close over ride.
24. Device permissive ok.
FEED WATER PUMP START PERMISSIVES
1. LP comp drum level low.
2. Suction isolation valve open FB.
3. HP discharge MOV closed and HP bypass MOV closed or HP discharge header pressure.
4. IP discharge MOV close FB.
5. ACW system in service FB.
6. CCW system in service FB.
7. Lube oil pressure ok.
8. Lube oil temperature high.
9. Lube oil motor pump running.
10. FWP bearing temp hi.
11. FWP motor bearing temp hi.
12. FWP vibration hi.
13. FWP motor winding temp hi.
14. FWP RRS speed actd.
15. FWP suction pressure low.
16. Lube oil level low.
17. Trip over ride.
18. Device permissives ok.
CEP START PERMISSIVE
1. CEP discharge header pr not LL or discharge MOV closed.
2. Condensate hot well level low.
3. Suction isolation valve open FB.
4. Motor bearing temp hi.
5. Motor winding temp hi.
6. CEP vibration hi.
7. Trip over ride.
19. Device permissive ok.
CIRCULATINDG WATER PUMP START PERMISSIVE
1. CW supply isolation valve open FB.
2. CW INTK CHMB DS diff level hi.
3. CW INTK CHMB CCRBS diff level hi.
4. CWP discharge HOV closed.
5. Motor bearing temp hi.
6. Motor winding temp hi.
7. Vibration hi.
8. RRS actd.
9. Forebay chamber level low.
10. Header pressure not low. >0.5 bar.
11. Water box vacuum system in auto.
12. CW pump-A auto.
13. CW pump –B auto.
14. Condenser inlet water box -1 CW MOV auto.
15. Condenser inlet water box -2 CW MOV auto
16. Condenser outlet water box -1 CW MOV auto
17. Condenser outlet water box -2 CW MOV auto
18. CW DBRS ready.
19. CWP-A discharge HOV HPU ready.
20. CWP-B discharge HOV HPU ready.
21. CWP-A VFD DCS mode.
22. CWP-B VFD DCS mode.
CW START PERMISSIVE SUB GROUP
1. CWP-A auto.
2. CWP-A VFD DCS mode.
3. CWP-A discharge HOV HPU ready.
4. CWP-A Dis HOV auto.
ACW PUMP START PERMISSIVE
1. Pump discharge header pressure LL or Discharge MOV closed.
2. Bypass MOV close FB.
3. Suction header pressure low.
4. Trip over ride.
5. Device permissive ok.
CCW START PERMISSIVE
1. Pump Bearing temp hi.
2. Motor bearing temp hi.
3. Vibration hi.
4. Motor winding temp hi.
5. Expansion tank outlet MOV open FB.
6. Minimum recirculation FCV in auto or open.
7. Expansion tank level not low.
8. Trip over ride.
9. Device permissive ok.
10. CCWP-A in auto.
11. CCWP-B in auto.
12. CCW expansion tank out MOV in auto.
13. CCW expansion tank LCV in auto.
14. CCWP min recirculation FCV in auto.
15. CCW supply to STG area MOV in auto.
16. CCW supply to HRSG area MOV in auto.
17. Common CCW return header to block MOV in auto.
18. Block to common CCW supply header MOV in auto.
19. CCW expansion tank level ok.
20. CCWP-A or CCWP-B ready.
CONDENSER VACUUM SYSTEM START PERMISSIVE
1. ACW system in service FB.
2. Vacuum breaker closed.
3. Seal steam pressure > 1.28 bara.
4. Condenser vacuum system in auto.
