Emergency Operation in Santaldih Thermal Power Station

7/29/2019 Emergency Operation in Santaldih Thermal Power Station

1/23

LMI 2

MECHANICAL OPERATIONEMERGENCY OPERATION

STPS, PURULIA

WBPDCL


2/23

EMERGENCY INSTRUCTION FOR TOTAL AC SUPPLY FAILURE

CONSEQUENCES OF TOTAL AC FAILURE:

For the entire station:

1. 220KV Main bus-1 & 2 dead.2. 132KV bus dead.3. 220KV/132KV, 100MVA TIE TR. Tripped.4. 220KV/132KV/33KV, 130 MVA TIE TR. Tripped.5. All Out going Feeder Tripped such as

For 220KV side

Chandil(Bus capacity - 300 MW)

Bishnupur-1 & 2(Bus capacity - 300 MW)

Durgapur-2(Bus capacity - 300 MW)

Asansol(Bus capacity - 300 MW) Bishnupur-3 & 4( yet to be commissioned), (Bus capacity - 300 MW)

For 132KV side

Purulia-1 & 2(Bus capacity - 130 MW)For 33KV side

Bhojudih-1(Going power to Township) (Bus capacity - 7.5 MVA)

Bhojudih-2(Bus capacity - 7.5 MVA)6. ST-1 & ST-2 (132KV/6.6KV), ST-3(220KV/6.6KV), ST-4 (220KV/6.6KV), ST-

5(220KV/6.6KV) Tripped.7. All 6.6KV station bus dead ( such as OSA, OSB, OSC, OSD for unit-5&6 and

Stn#1,Stn#2,Stn#3A&3B bus for existing unit side dead).

For unit5:

1. OSA & OSB Tripped.2. 5SA & 5SB becomes dead.3. All 415V MCC including emergency MCC 5EA&5EB becomes dead

For unit 6:

1. OSC & OSD Tripped.2. 6SA & 6SB becomes dead.

3. All 415V MCC including emergency MCC 6EA&6EB becomes dead


3/23

UNIT RESPONSE AND EMERGENCY ACTIONS TO BE TAKEN:

The following are very important actions to be taken immediately after total AC

supply failure:

1. D.C. seal oil and D.C. Emergency oil pump are put in service in both units (DCSOP& DC EOP takes start from hard contact).If the above said pumps are nottaking start from hard contact , start it from local panel.

2. Start DG set of the corresponding unit (DG set normally come into service in auto)and charge emergency MCC. If DG set is not taking start in any unit start the otherunit DG set and close the bus coupler. Check normal I/C from unit bus ofrespective emergency MCC remain open. Note down all the flags of 6.6 KV / 0.415KV bus & reset them. Ensure DC lights of UCB are on.

3. If no seal oil pump in service in any unit, arrange for H2 purging.

4. The lube oil to seal oil system interconnection valve open automatically when sealoil header pressure fall below 8Kg/Cm

2and vent H2 pressure till DP in control

room is at least 0.5 Kg/cm2.5. Start DC jacking oil pump.6. Start DC Scanner air fan7. Ensure DC lighting coming into service.8. Ensure all the breakers in switchyard are tripped. Even if breakers are tripped give

trip command to all the breakers from switchyard.9. Monitor the operation DC drives and DC bus voltages.10. Ensure emergency lights are ON11. Start AC SOP-2 and stop DC SOP.

12. Start AOP-2 and stop DC EOP.13. Start AC JOP and stop DC JOP.14. Close turbine side drains to flash box manually if any are open15. Close all extraction block valves manually.16. Keep HP and LP bypass in closed condition.17. Close the Gland steam and ejector Supply valve manually from PRDS.18. Close Aux PRDS MS line Isolating valve.19. If necessary close MS v/vs. (boiler side) manually.20. Start diesel fire water pumps, sprinkler pump.21. Hand barring of turbines is to be ensured if barring gear is not coming into service

(Hand barring is to be given at every 30min. interval).

22. Open the vacuum breaker below 2000 rpm.23. Trip command is given to all 6.6 kV breakers and removes all standby drive.24. Closing of LFO Trip / nozzle isolation valves manually in all units.25. Close soot blower steam isolation v/v if blowing is in progress before power failure.26. Close boiler drains (CBD, IBD) if open.27. Ascertain cause of Power failure and confirm from switch yard.28. Open Generator Breaker Isolator manually from local29. Inform to all higher authorities.

To avoid

rupture of

LP Turbine

diaphragm


4/23

Restoration Procedure for AC Supply

1. When total power failure occurs DG set-1(for U-6) & DG set-2(for U-5) should start

automatically. If not, then start DG set manually and close DG set outgoing bkr. toDG PCC & Incomer bkr to Emergency MCC. Check normal I/C from unit bus ofrespective emergency MCC remain open.

2. Open all 220KV bkrs which are not tripped.

CASE-I:3. Interact with SLDC and if 220 KV BUS is normal i.e if power is available from 220KV

side then in consultation with SLDC charge 220 KV BUS through any 220 KV feeder(from ECR). After charging the BUS normalize the following bays one by one.

I. 220 KV bkr. Of ST#3(from GCR)II. 220 KV bkr. Of ST#4(from GCR)

III. 220 KV bkr. Of ST#5(from GCR)IV. 220 KV bkr. Of 100 MVA TIE TR. (from ECR)V. 220 KV bkr. Of 130 MVA TIE TR. (from ECR)

4. Normalisation of 132 KV bus:

Normalise 132 KV bus after charging any TIE TR (100 MVA or 130 MVA). (FromECR)

Close 132 KV bkr. of ST#1 & ST#2 TR.(from ECR) Close 132 KV bkr. of PURULIA#1 & PURULIA#2 feeder.(from ECR) Normalise 6.6 KV Stn#1, Stn#2, Stn#3A& Stn#3B bus. After that charge the

Lighting Transformers and normalize all lighting panels & AC Distribution

board.(from Switchgear#1&2)Simultaneously take action for normalization of other 220 KV feeders.(from ECR)

CASE-II:5. If SLDC asked ECR to take power from DVC, then charge PURULIA-2 feeder from

132KV side. After charging the 132KV BUS normalize the following bays one byone.

220 KV bkr. Of 100 MVA TIE TR. (from ECR). 220 KV bkr. Of 130 MVA TIE TR. (from ECR). 220 KV bkr. Of ST#3(from GCR). 220 KV bkr. Of ST#4(from GCR). 220 KV bkr. Of ST#5(from GCR). Close 132 KV bkr. of ST#1 & ST#2 TR.(from ECR). Normalise 6.6 KV Stn#1, Stn#2, Stn#3A& Stn#3B bus. After that charge

the Lighting Transformers and normalize all lighting panels & ACDistribution board.(from Switchgear#1&2)

6. For normalization of station bus & unit bus of U#5 &U#6(from DCS):After charging of ST#3 & ST#4 Close 6.6 KV incomer breakers of OSA, OSB, OSCand OSD Bus. At present situation OSD Incomer is not available. For normalizationof OSD bus, close both Tie bkr. of OSB with OSD at U#5 switchgear & U#6


5/23

switchgear. Close Tie Bkr. Of Station Bus & Tie Bkr. Of Unit Bus also. Beforeclosing of Tie bkr. Of 5SA & 5SB put the BTS selector switch in OUT position.Reset all under voltage relays at U#5& U#6 switchgear.

After normalization of 6.6 KV station & unit bus charge Unit PCC & Station PCCbus & Emergency MCC bus of two units.

Isolate DG from Emergency bus after synchronization with grid and stop DGsets. Energise all outgoing transformers (6.6 KV/415 V) & normalize all outgoing

feeder bays (i.e. Boiler MCC & Turbine MCC) of two units. Normalise all lightingpanels of New Units.

7. Start APH electric motor.8. Start ACW p/p A or B.9. Start one CW p/p after proper venting.10. Start DMCW (T) P/p and DMCW (B) P/ps.11. Start IAC and PAC as per requirement to maintain header pressure.12. Start service water p/p and maintain hotwell normal level.13. Ensure BFPs lub oil p/ps and APHs are running.14. Changeover AOP-2 to AOP-1

15. Start normal light up process of Boiler & Turbine taking clearance with ECR.


6/23

UPS FAILURE:

CONSEQUENCE:

ACDB#A, B supply to FSSS, DCS, and UCP will cut off. On UPS power failure, Boiler MFT will act due to loss of 24V DC and all fuel will

be cut-off. Turbine will not trip due to non availability of 24V DC to RTS-1 & 2 (Remote Trip

Solenoid). So TG will have to be tripped by manual (Operating Two Leverlocated on Main Trip Valves) from local Governing panel.

No Turbine lub oil pumps will take start through SLC LOP i.e. auto (except EOPDC). So panel operator should keep attention in this point. Only DC EOP willstart from lub oil pr.


7/23

EMERGENCY INSTRUCTIONS IN CASE OF APH ON FIRE

CONDITION OF THE UNIT:

UNIT IS RUNNING AT 250 MW AND BOTH ID/FD AND APH RUNNING. 4 MILLS IN

SERVICE.

CONSEQUENCES:

Overall damage to the APH elements.

APH flue gas outlet temp. increase rapidly.

Also SA air and PA air outlet temp increase considerably.

Support brg temp increase considerably.

ACTION:

Reduce unit load to around 50%..

Stop the APH (which is on fire) and isolate APH from flue gas and air side by

closing inlet and outlet dampers immediately. Keep close watch to running APH flue gas DP.

Stop one top mill and reduce load to 150 MW and below as required by adjustingthe coal flow.

Stop one corresponding PA fan after loading the other PA FAN.

If flue gas inlet and outlet dampers are not closing then monitor the flue gasoutlet temperature and restrict it to 200 deg C

Wait until all temp. becomes normal.

Start APH electric motor again.

Inform fire & safety department.

Inform to higher authorities.

[Any APH may be allowed to run on air motor provided the flue gas

inlet temp of APH is maintaining within 370oC max.]

Parameters to be monitored

Flue gas temperature APH I/L and O/L, SA air i/L and O/L, PA air I/L

and O/L temp.

*** If Flue gas temperature at APH o/L above 200o C, trip the boiler.


8/23

EMERGENCY INSTRUCTIONS IN CASE OF APH TRIPPING


UNIT IS RUNNING AT 250 MW AND BOTH ID/FD AND APH RUNNING. 4 MILLS IN

SERVICE.

CAUSES OF TRIPPING

Motor electrical protection acted.

Uncommanded OFF.

Decoupled from gear box.

Control Engineers actions and unit emergency response:

Ensure that air motor takes start on auto. If it is not starting on auto, open the bypass valve of air motor solenoid valve and

put air motor in service.

Even then APH is not rotating, then isolate APH from flue gas and air side byclosing inlet and outlet dampers immediately.

Keep close watch to running APH flue gas DP.

Stop one mill and reduce load to 150 MW and below as required by adjusting thecoal flow.

Stop one corresponding PA fan after loading the other PA FAN.

Start second plant air compressor if air pressure is less than 5 Kg/cm2.

If flue gas inlet and outlet dampers are not closing then monitor the flue gas

outlet temperature and restrict it to 200 deg C.

[Any APH may be allowed to run on air motor provided the flue gas

inlet temp of APH is maintaining within 370oC max.]


Flue gas temperature APH I/L and O/L, air flow and plant air pressure

*** If Flue gas temperature at APH o/L above 200o C, trip the boiler.

***Start the tripped APH after rectification of problem and raise the

load to full.


9/23

EMERGENCY INSTRUCTIONS FOR ID FAN TRIPPING

CONDITION OF THE UNIT:UNIT IS RUNNING AT 250 MW AND BOTH ID/FD RUNNING. 4 or MORE MILLS IN SERVICE.

CAUSES OF TRIPPING

Motor electrical protection acted. Lub oil pressure v.lo< 0.4Kg/cm

2with 30sec time delay

H.C oil pressure v.lo 0.6Kg/cm2

H.C oil temp high 110oc

H.C oil cooler o/l temp 90oc

Winding temp v.hi 130oc with 2sec time delay (2 out of 6 logic)

Fan Bearing temp v.hi (105oc) with 2sec time delay. Motor Bearing temp v.hi (105oc) with 2sec time delay. Lub Oil relay operated

ID fan ON and i/l gate closed

ID fan ON and o/l gate closed

Uncommanded OFFCONSEQUENCES:

On ID trip, FD fan of the corresponding stream will trip.

Mills in excess of three will trip according to the logic.

Furnace pressure will get disturbed and poor flame condition will occur (may lead topartial flame failure due to fuel rich mixtures in the furnace and causes a lot offurnace disturbance).

Unit load will reduce to approx 155 MW (Run back active) if unit runs on CMC.

The other ID/FD fan may become overloaded if on auto.ACTION:

Cut in suitable elevation oil guns to stabilize the furnace keeping close watch onfurnace draft variation.

If m/c is on manual, reduce load immediately to around 155 MW keeping track ofdrum level, MS Pressure.

Running ID/FD fans, if in auto, will get loaded and maintain draft and airflow Keepwatch on their loading and if required, release ID/FD fans to manual & avoidoverloading.

If FD fan is in manual then increase the air flow in running FD fan manually, keepinga watch on ID and FD currents.

Reduce boiler firing from upper elevation to make it compatible with available airflow to avoid fuel rich furnace

Maintain the coal flow as per requirement observing the air flow.

Maintain O2 (3%-5%) in the flue gas.

Parameters to be monitored:Furnace draft, drum level, airflow, ID & FD currents, mill loading, TG load, MSpressure & temperature, RH temperature, WB to furnace DP, O2 %at APH i/l.

***Start the tripped ID/FD fan after rectification of the problem and raise the load to full.


10/23

EMERGENCY INSTRUCTIONS IN CASE OF FD FAN TRIPPING


UNIT IS RUNNING AT 250 MW AND BOTH ID/FD RUNNING. 4 Or MORE MILLS IN

SERVICE.

CAUSES OF TRIPPING:

Motor electrical protection acted. Winding temp v.hi 130

oc with 2 sec time delay (2 out of 6 logic).

Fan Bearing temp v.hi 105oC with 2 sec time delay (1 out of 6 logic).

FD Fan motor brg. temp v hi 1050C with 2 sec time delay (1 out of 6 logic).

FD fan ON and o/l damper not open in less than 2 minutes

Both FD Fans in service and one ID fan trip.

FD fan ON and lub oil pr. very low


11/23

EMERGENCY INSTRUCTIONS DURING PA FAN TRIPPING


UNIT IS RUNNING AT 250 MW AND BOTH ID, FD AND PA FANS RUNNING. 4 OR MORE

MILLS IN SERVICE.

CAUSES OF TRIPPING


Winding temp v.hi 120oc with 2 sec time delay (2 out of 6 logic).

Bearing temp (fan/motor) v.hi (105o

c) with 2 sec time delay (1 out of 6 logic). PA fan ON and o/l damper not open instantly.

PA fan ON and both lub oil pump OFF.

Uncommanded OFF

CONSEQUENCES :

PA Header pressure drops very fast and mills may trip due to this.

Mills in excess of three will trip according to the implemented logic. Unit load will reduce to approx 155 MW (Run back active) if unit runs on CMC. ACTION:

Ensure that tripped PA fan discharge damper closes and blade pitch comes tominimum position in auto, if not closing in auto, close it manually.

Running PA fan will get loaded to maintain PA Hdr Pressure, if it is in AUTO. Keepwatch on its loading and if required, release PA fan to manual & avoid overloading.

If 4 or more mills are running, mills in excess of three will get trip on auto. If any howthe mills do not trip then trip manually one by one maintaining the compactness andPA header Pr. If necessary cut out one more mill to maintain PA header pr.

Ensure that tripped mills HAG AND CAG will close. If they remain open, then close

manually. Cut in suitable elevation oil guns to stabilize the furnace keeping close watch on

furnace draft variation.

If m/c is in manual mode then reduce the load set point to 155 MW keeping track ofdrum level, MS Pressure according to the coal flow.


PA header pressure, running PA fan current, Furnace draft, drum level, mill loading,TG load, MS pressure & temperature, RH temperature.

***Start the tripped PA fan after investigation and raise the load to full.


12/23

EMERGENCY INSTRUCTIONS FOR ACW PUMP TRIPPING


UNIT IS RUNNING AT 250 MW AND BOTH ID, FD AND PA FANS RUNNING. 4 OR MORE

MILLS IN SERVICE

CAUSES OF TRIPPING:

Pump tripping due to discharge pressure low at 1.0 Kg/cm2, time delay 15 sec

Pump On and discharge valve closed for >5 sec

Pump on and discharge valve failed to open for >1 min

Motor Electrical protection operated.

ACW p/p DE/NDE brg. Temp very high > 100oC.

Motor winding temp > 120oC with 3 sec time delay.

Individual disch. Pr. > 4 Kg/cm2 or discharge header pr > 4 Kg/cm2.

Feed pool level< 5.5 m for 5 sec for unit-5. Feed pool level< 154.1 m msl for 5 sec for unit-6.

Pressing EPB from local.

Plant Response and control engineers actions:

Start the standby ACW pump if not taken start in Auto.

PHE outlet temperature will raise and may lead to unit tripping on coldgas temperature.

All compressors may trip due to DM cooling water temp high.

Maintain the load to maintain the cold gas temperature, ID and BFP

working oil temperature. If standby pump do not take start, start 2nd pump of adjacent unit and

open interconnection valve keeping close discharge valve of faulty unit,observing discharge header pr. of the healthy unit.

If the above operation fails then open the both ACW pump dischargevalves manually of the faulty unit. This will maintain some flow fromCW header.

Keep close watch on turbine lub oil temp.

Parameters to be monitored:

Cold gas temperatures, DMCW temperature, ID and BFP lube oil and working oil

temperatures, turbine lub oil temp.


13/23

EMERGENCY INSTRUCTIONS FOR CW PUMP TRIPPING AND STAND

BY PUMP FAILS TO START


UNIT IS RUNNING AT 250 MW AND BOTH CW PUMPS ARE RUNNING AND 4 MILLS IN

SERVICE.

CAUSES OF TRIPPING:

CW Pump motor bearing temperature very high (Time Delay :5 Sec) > 85 oC

CW Pump motor winding temp very high (TD : 2 Sec) >120 deg C

CW Pump thrust bearing temperature high(TD : 5 Sec) > 85 deg C

CW Pump sump level very low (TD : 5 Sec) < 5.5mtr for unit-5.

CW Pump sump level very low (TD : 5 Sec) < 154.1 m msl for unit-6

CW Pump motor electrical protection operated

CW Pump discharge v/v failed to open (TD:10 Sec)

CW Pump on , discharge butterfly v/v closed (TD : 5 sec ). CW p/p on & common dischage pr. > 4.4 Kg/cm

2.

CW p/p on & individual discharge pr > 4.5 Kg/cm2.

Plant Response and Control engineers actions:

CW PUMP tripped alarm comes in DCS. Ensure tripped CW pump discharge valvein closed condition.

Unit load will reduce to approx 155 MW (Ran back active) if unit runs on CMC.

If m/c in on MAN mode reduce load to around 150 MW.. Cut in suitable elevation oil guns to stabilize the furnace keeping close watch on

furnace draft variation.

Condenser vacuum will deteriorate due to low CW flow.

Trip one top mill and reduce load observing the vacuum.

Turbine vibration may increase due to sudden CW flow disturbance.

With one CW pump load can be maintained nearly 155 MW observing the vacuum.

Parameters to be Monitored:

CW flow, Condenser vacuum, CW I/L and O/L temp., MS pr and temp., RH temp.

***Start the tripped CW pump after rectification of the problem and raise the load tofull.


14/23

EMERGENCY INSTRUCTIONS IN CASE OF BFP TRIPPING


UNIT IS RUNNING AT 250 MW AND TWO BFPS RUNNING AND 4 MILL IN SERVICE.

CAUSES OF TRIPPING

BFP ON and main pump Suction Pr. Low < 10 Kg/cm2 time delay 10 sec

Lube oil at common Header pr. Low < 0.5 Kg/cm2 for 2 sec

Working oil temp at I/L to working oil cooler > 130 deg C

Differential temp across BFP main pump discharge & suction high for 3 sec>15C and suction flow 60C

BFP Bearing temperature high > 90 deg C with time delay 2 sec.

BFP hydraulic coupling bearing temp >100 deg C time delay 2 sec

BFP Booster pump thrust bearing metal temp high 100 C with time delay 2

sec. BFP motor winding temp high 125 deg C time delay 2 sec

Dearator level very low three level switches -2476 mm(2/3 logic).

BFP motor brg. DE/NDE temp.>90oC with 2 sec time delay.

Motor electrical protection operated.

6.6KV bus failure.

Control Engineers actions and unit emergency response:

CASE 1: Running BFP Tripped and standby BFP taken Auto start at rated scoop.

Action: -

1. Keep close watch on running BFP scoop and current to avoid overloading.2. Ensure recirculation valve of auto start BFP will close and observe its

discharge flow. Try to maintain Drum level in auto and if required maintaindrum level in manual..

3. Reduce load by 15 to 20 MW in the unit as a safety precaution.4. After maintaining drum level normalize the unit load.

CASE 2: Running BFP Tripped and standby BFP not taken Auto start.

Action: -1. Unit load will reduce to approx 155 MW (Run back active) if unit runs on CMC2. Keep close watch on running BFP scoop and current to avoid overloading.3. If requred take running BFP scoop in MAN mode to avoid overload of running

BFP and maintan drum level manually.4. Cut one running top mill as safety precaution to maintain Drum level5. Start standby BFP and increasing its scoop manually, ensure its recirculation

valve close and observe its discharge flow. Try to maintain Drum level..6. After maintaining drum level both BFP scoop taken in auto and normalize

the unit load.


15/23

CASE 3: Running BFP Tripped and standby BFP Failed to start.

Action:

1. Unit load will reduce to approx 155 MW (Ran back active) if unit runs onCMC

2. Keep close watch on running BFP scoop and current to avoid overloading.3. If required take running BFP scoop manually to avoid overload of runningBFP .

4. Cut one top running mill and if required take one suitable elevation oil gunin service to stabilize furnance keeping watch on furnace draft variation.

5. Try to maintain Drum level with running BFP. Reduce load till drum level iscomfortable with BFP flow of 440 tph.

6. After maintaining drum level, put the drum level on auto.

CASE 4: Running one or two BFPs Recirculation valve open suddenly.

Action:1. Try to close the recirculation valve from control room, if it is not closing,

start standby BFP and increase its scoop manually.2. Reduce load as required to maintain Drum level.3. Try to close the recirculation valves and normalize the load.


Drum level, FCS control valves opening, BFPs current and other parameters, mill

loading, TG load, MS pressure & temperature, RH temperature.

***after rectification of problem, raise the unit load to full with two BFPs.


16/23

EMERGENCY INSTRUCTIONS IN CASE OF ONE CEP TRIPPING


UNIT IS RUNNING AT 250 MW AND ONE CEP RUNNING

CAUSES OF TRIPPING Motor electrical protection acted.

Motor Bearing temp very high (90oc)

Pump bearing temp very high (95 deg C) Motor winding temp very high (130 deg C) Hot well level low low < 400 mm

CEP discharge header pressure very low < 15 Kg/cm2 for 5 sec.

Plant Response and Control engineer actions:

Unit load will reduce to approx 155 MW (Run back active) if unit runs on CMC. Cut in suitable elevation oil guns and if required stop one top mill to take care of

deaerator level.

If running CEP trips standby pump takes start on auto.

If it is not taking start on auto, the standby CEP permissive like discharge valveclosed and discharge vent valve open are required to start the standby pumpmanually, then start the p/p manually.

Close the discharge valve of tripped pump immediately..

If required take starting ejector in service.

Stop one top mill Immediately and reduce the load to 155 MW (if m/c is on MANmode) to take care of deaerator level.

Reduce the load set point keeping track of drum level, MS Pressure according tothe coal flow.

Normalize the load after CEP is running normal.


CEP header pressure, condensate flow, deaerator level, feed water flow, hotwell level,

condenser vacuum, LPH levels.

***Ensure the availability of standby CEP after rectification of the problem.


17/23

EMERGENCY INSTRUCTIONS IN CASE OF TWO CEP TRIPPING

Plant Response :

TG may trip on low vacuum, deaerator level very low,all BFP trip.

Boiler may not trip on reheater protection as both CEP unavailable.

Vacuum will deteriorate as main ejector is starved from water side.

GSC header pressure will fluctuate & vacuum deteriorate.

GSC & drain cooler may damage due to water side starvation.

Control engineer actions:

If CEP tripping is from hot well level very low, immediately open hot well normalmake up valve DM-50 and hot well emergency make up valve DM-46 fromCSTand start DMSW p/p.

If CEP tripping due to other reason, try to start CEP & meanwhile take startingejector in service.

Immediately reduce load to around 40 MW. Keep on watching drum level & BFP master response.

Open the bypass of seal steam leak off valve to maintain header pressure steamflow in GSC become stagnant (due to water side starvation) & open MAL drain ofthat header.

Cut out LPH from steam side.

Close super heater & reheater attemperation block valve.

Deaerator level will come down very quickly. In extreme condition deaeratoremergency make up line can be opened cautiously because of hammeringpossibility.

If condition does not improve, immediately hand operate MFT push button to

trip the boiler as it will not trip on reheater protection after turbine trip as LPbypass will not open on both CEP tripping.

***** If Auto start of 3rd CEP do not take place or M/C is running without anyCEP, then immediately hand operate MFT push button to trip the boiler onreheater protection after turbine trip as LP bypass will not open on both CEPtripping.


18/23

DMCW(T) PUMP TRIPING EMERGENCY

CAUSES: -

Pump tripping due to Bearing temperature high ( 1000

C ,Time delay 2 sec).

Pump tripping due to Motor winding temperature high (130o

C, time delay 3 sec)

Pump tripping due to Suction Pressure low (at 1.5 Kg/cm2, time delay 5 sec)

Motor tripped due to 6.6 kV bus de-energize or any electrical relay operated.


EFFECTS :-

Generator cold gas temperature will increase, lead to turbine trip at cold gas temp55oC.

BFP working oil and lub oil temperature will increase.

CEP thrust pad temp may increase lead to CEP tripping at 95oc.

All compressor trip.

Lub oil temperature of all auxiliaries in turbine increasing.

Compressor (Instrument Air & Plant Air) lub oil temperature increasing.ACTION TAKEN :-

After tripping of running DMCW(T) pump ,ensure standby pump taken autostart .Otherwise immediately start standby pump manually.

Analyze cause of tripping of running DMCW(T) and after rectification of problemtripped DMCW(T) taken in standby (after checking its healthiness).

If S/B pump failed to start, open interconnection valve (after running 2nd

DMCW(T) p/p of the adjacent unit) only for compressor cooling isolating othercooling water supplies.

DMCW(B) PUMP TRIPING EMERGENCY

CAUSES: -

Pump tripping due to Bearing temperature high ( 1000

C ,Time delay 2 sec)

Pump tripping due to Motor winding temperature high (130o C, time delay 3 sec)

Pump tripping due to Suction Pressure low (at 1.5 ksc, time delay 5 sec)

Motor tripped due to 415 V bus de-energize or any electrical relay operated.


EFFECTS :-

Lub oil temperature of all auxiliaries in boiler increasing.


19/23

ID fan working oil and iub oil temperature will increase.

ACTION TAKEN :-

After tripping of running DMCW(B) pump ,ensure standby pump taken auto start.Otherwise immediately start standby pump manually.

Analyze cause of tripping of running DMCW(B) and after rectification of problemtripped DMCW(B) taken in standby (after checking its healthiness).

EMERGENCY INSTRUCTIONS IN CASE OF TURBINE LUBE OIL

TEMPERATURE HIGH OR LOW


UNIT RUNNING AT FULL LOAD OF 250 MW.

LUBE OILTEMPERATURE LOW:

CAUSES:

1. Water side valves in oil coolers are open more than required. (Especially lowload and unit stopped condition).

2. Lube oil temperature may be malfunctioning.3. In cold season CW temp. may be very low4. Oil temperature control valve malfunctioning.

EFFECT:

1. Unstable oil film in bearings which may damage the bearings.2. Turbine bearing Vibration may rise.

ACTIONS TO BE TAKEN:

1. Throttle the cooling water valves of the oil coolers (if required).2. If the machine is off load, do not roll it till oil temperature attains an acceptable

working value( 44oC)..

3. If the machine is on load, temperature should be rapidly raised to theacceptable.

4. Oil centrifuge to be kept in service with all heaters.


20/23

TURBINE LUBE OIL TEMPERATURE MAINTAINING HIGH:

CAUSES:

1. ACW pump trip.2. Oil temperature control valve malfunctioning.3. Oil cooler water side inlet or outlet valve closed.4. Oil coolers are dirty. (Heat transfer is very low).5. Air locking in oil coolers.

Effect:

1. Rise in bearing Metal temperature and will lead to tripping of turbine on bearingtemperature high.

2. Rise in seal oil temperature.

ACTIONS TO BE TAKEN:

1. Check operation of lube oil temperature controller, if not functioning in auto taketo manual and control the temperature.

2. Open the ACW valves of the coolers if they are throttled or closed.3. If ACW pressure is low, changeover ACW pump or hand tight stand by ACW p/p

discharge valve.4. Vent the oil coolers on water side.5. Trip the unit if lubricating oil temperature rises continuously and is uncontrollable.6. External cooling of oil cooler can help to bring down oil temperature.


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EMERGENCY INSTRUCTIONS IN CASE OF INSTRUMENT AIR

COMPRESSOR TRIPPING


UNIT IS RUNNING AT 250 MW AND BOTH ID/FD RUNNING AND 4 MILLS IN SERVICE.

CAUSES OF TRIPPING


Motor Winding temp v.hi 110oc

Bearing temp very high 110oC EPB PRESSED

1ST STAGE (LP CYLINDER) TEMPERATURE HIGH > 205 DEG C

2ND STAGE (HP CYLINDER)TEMPERATURE HIGH >205 DEG C

LUB OIL PRESSURE LOW (TD: 15 SEC.) TRIP> 1.5 bar

LUB OIL TEMP. VERY HIGH > 65oC

CIRCULATING WATER FLOW LOW (TD: 10SEC.) TRIP

Operator actions and unit emergency response:

Immediately monitor instrument air pressure and it may take approximately few minutesto drop to critical value of instrument air pressure.

Start standby instrument air and plant air compressor and open interconnectionbetween IAC and PAC (If not opened previously).

If air pressure drop is due to leakage then isolate the leakage section.

Critical instrument air pressure is around 4 Kg/cm2

below which many valves willmalfunction.

All BFPS recirculation valves will open.

Feed control station control valves may stay put below 4 Kg/cm2.(if stay put block do

not function successfully then FCS control v/v may close below 4 Kg/cm2)

If FCS control valve is closing, to be opened manually. SH and RH attemperation valves (also stay put in nature) will close if stay put block do

not operate successfully.

CEP min recirculation v/v (stay put in nature) will open if stay put block do not operatesuccessfully.

Unit may trip due to drum level very low.

Start standby CEP and BFP to maintain deaerator level and FW flow.

Trip one top mill and reduce load to 175 MW.

BFP scoop will be inoperative. Operate the scoop manually and maintain drum level.

Maintain hotwell and deaerator level through bypass motor operated valve.

If guns are in service guns, will trip.

LDO trip valves will close.

All elevation LONV will close. AT 4 KSc (approx) FOLLOWING VALVE WILL OPEN :

o Deaerator overflow valve DR-38.o NORMAL MAKE UP TO HOTWELL DM 35


Drum level, instrument air pressure, service air pressure, deaerator level, hotwell level, feed

water flow, MS and HRH temperatures.


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EMERGENCY INSTRUCTIONS IN CASE OF HYDROGEN LEAKAGE

FROM GENERATOR

CAUSES OF LEAKAGE:

1. SEAL OIL SYSTEM TROUBLE AND ALL SEAL OIL PUMPS NOT RUNNING.

2. LEAKGE FROM SEALS.3. HYDROGEN LEAKGE FROM GENERATOR BUSHING.4. ANY OTHER MAJOR LEAKAGE RESULTING IN DROP OF PRESSURE.

Operator actions and unit emergency response:

1. Start charging hydrogen cylinders immediately and maintain rated hydrogenpressure.

2. Monitor generator winding and cold gas temperatures.3. Reduce load to 180 MW by tripping one top mill if pressure is not maintaining.4. If rate of drop is very fast, trip the unit if hydrogen pressure drops below 2.0

Kg/cm

2

5. Immediately start hydrogen purging if pressure falls below 0.3 Kg/cm2

with CO2.6. After getting CO2 purity clearance from chemistry, start CO2 purging with air.

Maintain seal oil DP.


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Documents

Emergency Operation in Santaldih Thermal Power Station