IDENTIFICATION OF TOTAL AC FAILURE | ||||||||||||
Simultaneous happening of the following: | ||||||||||||
Unit tripping. | ||||||||||||
All HT, LT drives tripping. | ||||||||||||
400KV, 11KV, 3.3 KV Bus dead. | ||||||||||||
DC lights getting on. | ||||||||||||
DG set starting in auto. | ||||||||||||
1. Ensure starting of following equipments on auto otherwise start manually/from Local starting panels : | ||||||||||||
Main TG DC EOP. | ||||||||||||
DC Seal oil pump. | ||||||||||||
DC EOP of TDBFP – A & B. | ||||||||||||
DC Scanner fan. | ||||||||||||
DC JOP at TG speed of 510RPM | ||||||||||||
All Air heaters air motor. | ||||||||||||
Switch on DC lighting if does not come on auto. | ||||||||||||
2. Charge Cooling water of CC pumps | ||||||||||||
from Emergency overhead tank. (Open vent Valve in the cooling water return line to establish flow. Keep close watch on cavity temp of all CC pumps.) | ||||||||||||
3. Emergency bus charging | ||||||||||||
Emergency bus charging through DG incomer & BC closing on auto otherwise do it manually /from Local after ensuring tripping of both normal incoming breaker.(ensure no fault in relay) | ||||||||||||
If both DG sets does not come on auto, start it manually & charge emergency bus. | ||||||||||||
4. To avoid rupturing of LPT and TDBFPT diaphragms :- | ||||||||||||
Ensure opening of vacuum breaker. Give manual open command also. | ||||||||||||
Close Turbine & TDBFP A&B seal steam supply valves from UCB. Close manual isolating valves from Local. | ||||||||||||
Close all Mall drains. | ||||||||||||
Close all drain valves to SDFT & HP/LP Flash Tank. | ||||||||||||
Close MS – 1 & 2 valves. | ||||||||||||
Open MS strainer drains to UFT and CRH Pot drain to atmosphere. | ||||||||||||
Isolate CRH/Aux steam to Deareator | ||||||||||||
5. Ensure the following equipments running once Emergency bus gets charged through DG: | ||||||||||||
Main TG : AOP 2, AC seal oil pump 2,H2 side seal oil pump,AC JOP , Vapour extraction fan 2 of MOT and Gen. Brg.chamber fan 2 | ||||||||||||
TDBFP A&B: AOP 2, JOP, Vapour extraction fan 2. | ||||||||||||
Boiler : AC Scanner air fan, AC lighting.(ELP) | ||||||||||||
Electric motors of all APHs. Air motors stops. | ||||||||||||
Stop DC equipments whose corresponding AC is started | ||||||||||||
6. Stop stand by DG set & monitor DG set diesel level, Winding, engine temperature | ||||||||||||
7. Ensure opening of barring gear valve at 210 RPM. Do hand barring if does not come on barring. Maintain Following parameter to avoid stalling of barring:- | ||||||||||||
Maintain TG lub oil temperature 55-60 degree | ||||||||||||
Maintain TG JOP pressure > 150 ksc & run both TG AOP | ||||||||||||
Maintain hotwell level -150 mm | ||||||||||||
8. Put TDBFP-A & B on barring | ||||||||||||
9. Run DG fire pump.(Monitor FW tank level) | ||||||||||||
10. Note down relay flags on :- | ||||||||||||
11KV / 3.3KV buses. | ||||||||||||
Generator protection panel. | ||||||||||||
Boiler/Turbine first up cause of tripping | ||||||||||||
11. Observe the following parameters closely :- | ||||||||||||
Hydrogen pr. from local gauge & UCB. | ||||||||||||
Purge Hydrogen by CO2 in case of problem in maintaining Seal oil DP. | ||||||||||||
12. Check 220 Volt, 24V and UPS charger came on load & monitor voltage. | ||||||||||||
13. Ensure following isolations after unit tripping:- | ||||||||||||
Ensure closing of HOTV / LOTV | ||||||||||||
Isolate SH / RH / HP bypass spray isolating valves | ||||||||||||
Isolate all oil guns | ||||||||||||
Isolate soot blowing steam line if charged | ||||||||||||
Switch off all ESP fields | ||||||||||||
Ensure closing of HP/IP stop & control valves | ||||||||||||
Ensure closing of all turbine extraction valves | ||||||||||||
Restoration of supply and normalization | ||||||||||||
Charging of 400kv buses and ST#3 | ||||||||||||
Normalize 11KV station bus 3SA, Normalize Unit buses through UT/Station Bus. Normalize 3.3 KV switch gear UAA both sections. | ||||||||||||
Normalize Switchgears :USS,SSS,TMCC,BMCC,Service Building MCC,ESP MCC,Offsite Switch Gears (Charge all 3.3 KV / 415 V Switch gear independently) | ||||||||||||
Normalize Emergency Bus from USS:- Synchronize UES with USS and close I/C from USS. OR Charge dead bus by putting DG on manual and closing I/C from USS. Trip the DG breaker and stop DG Set.(While dead bus charging, first of all changeover all the running drives in EMCC) | ||||||||||||
Normalize supply of PT plant, DM Plant Fire pump house, CW MCC, SACW, ASH HANDLING MCCs, AC MCC,FOPH MCC etc. | ||||||||||||
Start DM make up pumps | ||||||||||||
Start electric fire water pump & stop DG fire pump | ||||||||||||
Start Raw water pump & start CLW pump for Forebay/OAC makeup. Start SACW and service water pumps. | ||||||||||||
Run Main Plant A/C System. | ||||||||||||
Prior to start 11KV equipments, take permission from Switchyard Control Room.This is to avoid overloading of station Transformer. | ||||||||||||
Start CW pumps (Before starting ensure discharge valves are closed and vent valves in condenser inlet / outlet ducts are open). Charge both passes of condenser. | ||||||||||||
Start ACW and ECW pumps. | ||||||||||||
Start Instrument and plant air compressor and maintain header pr 6 ksc | ||||||||||||
Start CEP | ||||||||||||
Start oil pump (LDO/HFO) & charge oil lines on the short recirculation. | ||||||||||||
Start MDBFP and fill the Boiler drum up to normal level. | ||||||||||||
Charge aux. PRDS (MSPRDS may also be opened slightly to maintain adequate seal steam temp otherwise open PRDS drains and seal steam drains | ||||||||||||
Normalize the system further for unit synchronization: | ||||||||||||
Start stator water pump | ||||||||||||
Start CF pumps & its vapour fan. Put recirculation pumps in service | ||||||||||||
Start LOPs of ID/FD/PA/MILLS/APH | ||||||||||||
Maintain hotwell, deareator & drum level | ||||||||||||
Maintain HFO pressure 16 ksc & temperature 120 degree | ||||||||||||
Take round of Boiler and TG area for any abnormal sound/ water /steam /oil leakages/any hammering | ||||||||||||
Start ID/FD fan & start purging | ||||||||||||
Put HFO in long recirculation and maintain HFO temperature >115 degree | ||||||||||||
Light up boiler with 04 LDO oil guns | ||||||||||||
Charge APH soot blowing from PRDS | ||||||||||||
Open CBD & Eco recirculation valve | ||||||||||||
Start vacuum pump & observe condenser vacuum | ||||||||||||
Charge TG & TDBFP gland sealing system at -0.2ksc | ||||||||||||
Open drains of MS/CRH/HRH/ Mall drains | ||||||||||||
Open drains before boiler stop valve | ||||||||||||
Charge MS lines | ||||||||||||
Charge HP/LP bypass valves | ||||||||||||
Raise boiler & turbine rolling parameters as per starting procedure |
Thursday, May 10, 2018
Station Black-out
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