TURBINE EMERGENCIES

TURBINE EMERGENCY

TURBINE EMERGENCY
Turbine Trip
Boiler Feed Pump trip
Condensate Extraction Pump / Pumps Trips
Condensate Booster Pump Trip.
Dearator Level High.
Dearator Level Low.
H.P. Heater level High.
 L.P. Heater 3, 4, 5  level High.
Turbine Lub. Oil pressure Low.

TURBINE EMERGENCY
Lubricating Oil Temperature High.
Lubricating Oil Temperature Low.
C.W.Pump / Pumps Trip.
Fire in Turbine oil system..
Loss of Vacuum.
Exhaust hood temperature high.
Turbine Bearing Temperature High.
Axial Shift High.

TURBINE EMERGENCY
Eccentricity Highh.
Differential expansion High. ( Positive)
Differential expansion negative.
Bearing Vibration High.
Curtise Stage Pressure High.
Loss Of Barring Gear.
Condensor tube Leakage.
One side Quick closing valve or Interceptor valve close.
Water Induction in Steam turbine.

TURBINE EMERGENCY
Hydrogen Pressure Drop below permissible limit.
High Hydrogen Gas Pressure.
Hydrogen Purity Low.
Water Oil in Generator.
B.C.W. System Failure.
Instrument Air Failure.
1> TURBINE TRIP
CAUSE
Class B operated
Class A operated
MFT operated
Turbine over speed
Lub. Oil Pressure low
Distributing oil pressure low
Low condensor vacuum
Axial shift high
Hydro mechanical
Electromagnatic

1. TURBINE TRIP
CAUSE (cond..)
Low frequency
Turbine trip Push button pressed
Turbine trip Emergency leaver operated
L.P. heater 1 2 level high
Primary oil pressure high
Turbine Brg. Metal high.

*EFFECT
Turbine trip will actuate Class-A and MFT
Turbine Trip

Action:
Lit up the boiler
Find out the cause of the tripping and rectify
If it is not possible to roll turbine put it on B.G.
If every thing is O.K. reset turbine trip (class-B) relay.
Roll the turbine when turbine speed reduces to 1000 rpm ( if parameters permits)
Bring the turbine at 3000 rpm after giving required warm up time.
Keep watch on turbine diff. Expansion, Brg. Vib, & ecentricity

2. BOILER FEED PUMP TRIP

Cause:
Moter protection relay operated
Working oil temp. high
Discharge flow high
Discharge high
Suction pressure low
Lub. Oil pressure low
Moter brg. Temp. high
6.6 KV bus under voltage
2> BOILER FEED PUMP TRIP

Effect:
If stand by pump boiler drum level maintains.
If stand by pump does not start drum level may go very low which may trip the boiler

Action :

Start the stand by pump if it does not start on auto. Adjust the load to maintain the drum.
See the proper operation of recirculation valve warm up and C.W. valve.
Analize & rectify the fault in the main feed pump. Put it on Auto.
Restore the 6.6 Kv unit bus if it has lost and available the pumps.

3. Condensate extraction pump  Trip
CAUSE:
Moter protection relay operated. Or distrubance in that supply. ( fuse blown off)
Hotwell level low-low
415 supply auxillary supply failure.

Effect :
Deararter level fall.
Hot well level  will rise.
Condensor vacuum will fall.
Unit had to be tripped unless the CEP’s can be restored immediately.
3> Condensate extraction pump  Trip

Action:
If one CEP has tripped see that the standby CEP has started on AUTO or not. If npt start it on manual.
If the CEPs have found tripped on hot well level low- low build up the hot well level quickly and reset the hot well low low annunaction and start CEP immediately.
Reduce the unit load if the stand by CEP is not available to control the dearatoe level and rectify the problem in the CEP which has tripped.

4. Condensate Buster  pump Trip
CAUSE:
Expander level very high or very low.
415 supply auxillary supply failure.

Effect :
Deararter level fall.
If full load is being maintained Hot well level  will rise.
Action :
Expander level may go very high / very low due to trouble in expander level controller so take expander level controller on manual and try to maintain the expander level if it maintains starts CBP if it is on manual
4> Condensate Buster  pump Trip

Action :
If it is difficult to control to expander level CBP will trip frequently then reduce the unit load to maintain the dearater level.( If CBP fails to start then also reduce the unit load accordingly to maintain deararor level)
Also watch the hot well level if it is going very high then close the make up valve ( If it does not close on auto) and trip the condensate transfer pump and try to maintain the hot well level.
When ever CBP trips ensure the opening of Expander ldrain to hot well  and steam to condensate valve.

5. Dearator level high
CAUSE:
Excess make up to Hot well and faulty dearator level regulator.

Effect :
Risk of water entering to L.P. turbine gland through steam piping of L.P. gland if L.P. gland steam is being taken from Dearator.
Risk of entering the water in PRDS steam pipe line and the temperature of steam will fall.

Action :
Check the operation of dearator level controller if necessery take it on manual.
Change over the L.P. gland from dearator to PRDS If it is so
Open dearator drain 6 Ata PRDS drain and LP gland steam drain
Open surplus valve of hot well if it does not open on auto.

6. Dearator level Low
CAUSE:
Mal operation of make up valve.
Unauthorised clouser of valves between C.E.P. and dearator.
Boiler tube leakage.
C.B.P. not running at load more than 80 %.

Effect :
Danger of loss of suction pressure of boiler feed pump.
Drum level will go down.
To maintain the level we have to reduce the load on unit.

Action :
Check the operation of dearator level controller if necessery take it on manual.
Open the valve between CEP and Dearator if found close.
If the suction pressure is low and not increasing Switch Off the feed pump to allow unit to trip on Drum level low low.
If CBP trips at full loadreduce the load to 80 Mw.Maintain dearator level.

7. H.P. Heater level High
CAUSE:
H.P. eater drain to dearator level controller is faulty.( not operating properly) or control valve stuck up.
H.P. drain to L.P.H-5 valve does not open.
Dearartor pressure is higher thgan normal.
In adequate pressure to H..P. heater.
Tube failure in H.P. Heater.

Effect :
H.P. Heater drain to HPDFT will open to H.P. Heater level High.
H.P. Heaters get bypassed from water and steam side on auto.( If interlocks are through)
If level in H.P> Heaters builds up rapidely there is a possibility of water entering in to the turbine.
7> H.P. Heater level High

ACTION:
Take H.P. Heaters level controller on manual and maintain the level.
Check the operation of heaters’ drain to HPDFT valve, drain to LPH –5 valve open it manually if required.
Adjust dearator pressure , if it is more.
Adjust the steam attraction pressure if valves are throttle open them.
By pass HP Heaters manually if level is very high and are not getting bypassed on auto.

8. L.P. Heater 3,4,5  level High
CAUSE:
L.P. H – 3 level may go high due to difficulty in expander level controller and CBP trip.
LPH 4 & 5 level may go high due to difficulty in level controlling valve.
Tube failure in L.P.Heaters.
Low extraction pressure in LP heaters.

Effect :
Possibility of water entering in turbine if level is / are so high and uncontrollable.

8> L.P. Heater 3,4,5  level High

Action:
Check the level controllers of the heaters. If require take it on manual and try to maintain the level.
Adjust the extraction pressure if valves are throttle.
By pass the heaters (LPH- 3 & 4 ) if level LPH 3 and 4 is / are high and bypass the heater – 5 if level in it is very high and uncontrollable.

9. Turbine Lubricating pressure Low.
CAUSE:
Air lock in oil cooler.
MOP suction failure.
Duplex oil filter chocked up- line filter chocked up.
Leakage in oil lines. Flanges, bearings etc.
Excess oil consumption in generator seal oil system.
MOP failure.

Effect :
Rise in Brg. Metal temperature.
Turbine trips on lubricating oil pressure LO- Lo.
SOP – A SOP – B ACEOP & DCEOP start on auto at 0.8 Kg/Sq.Cm., 0.7  Kg/Sq.Cm., 0.6 Kg/Sq.Cm., lub oil pr. Respectively.
9> Turbine Lubricating pressure Low
Action:

Check oil pressure and adjust the pressure by adjusting LO 1 & LO 2 valves if possible.
Check for any oil leakage in the oil circuit.
Start in SOP
Trip the turbine if oil pressure does not improve.
Check the oil cooler , change over the defective one to the stand by. Remove the air lock from the cooler, if so.
Check the oil filter regularly, change over to stand by if difference in pressure increases get it cleaned Check the line filter spare & isolate them, whenever unit is in S/D and if required cleaning.

•