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POWER PLANT EMERGENECIES Presentation Transcript
1.POWER PLANT EMERGENECIES
2.Presentation outline
Boiler Emergencies
Turbine Emergencies
Generator Emergencies
Grid Failure
Boiler Emergencies
Turbine Emergencies
Generator Emergencies
Grid Failure
3.BOILER
4.HIGH FURNACE PRESSURE
One I.D. Fan tripped or Mal-operation
of control vanes of I.D./F.D./P.A. Fans or closing of damper
Unstable furnace flame conditions. Sudden starting of coal mill.
Furnace water seal broken, E.P. or flue gas path manhole opened.
Water wall tube rupture/leakage.
One I.D. Fan tripped or Mal-operation
of control vanes of I.D./F.D./P.A. Fans or closing of damper
Unstable furnace flame conditions. Sudden starting of coal mill.
Furnace water seal broken, E.P. or flue gas path manhole opened.
Water wall tube rupture/leakage.
5.ID FAN LUB. OIL PRESSURE / BEARING TEMP TROUBLE
Lub. oil pressure may be inadequate.
Lub. oil filters may be choked.
Greasing long overdue in fan bearings.
Corresponding alarm will indicate the problem area.
Lub. oil pressure may be inadequate.
Lub. oil filters may be choked.
Greasing long overdue in fan bearings.
Corresponding alarm will indicate the problem area.
6.ID FAN TRIP
Motor over-loaded.
Corresponding FD Fan has tripped.
Spurious electrical fault.
Lub. Oil pressure problem.
Bearing temperature problem.
Corresponding APH may have tripped.
Motor over-loaded.
Corresponding FD Fan has tripped.
Spurious electrical fault.
Lub. Oil pressure problem.
Bearing temperature problem.
Corresponding APH may have tripped.
7.FURNACE PRESSURE LOW
I.D. Fan auto control Failure.
I.D. Fan vane control mechanism Failure causing vanes to open wide.
Sudden decrease in air input or tripping of one F. D. fan.
Sudden tripping of one or more mills or choking of mill/raw coal Feeder pipe.
I.D. Fan auto control Failure.
I.D. Fan vane control mechanism Failure causing vanes to open wide.
Sudden decrease in air input or tripping of one F. D. fan.
Sudden tripping of one or more mills or choking of mill/raw coal Feeder pipe.
8.FD FAN TRIPPED
Motor over-loaded
Lub oil pressure trouble.
Bearing temperature trouble.
ID fan has tripped.
FD lub. Oil pressure low.
Motor over-loaded
Lub oil pressure trouble.
Bearing temperature trouble.
ID fan has tripped.
FD lub. Oil pressure low.
9.PA FAN TRIPPED
tripping is due to high bearing temp.
Boiler has tripped.
Lub. Oil pressure may be very low.
It will lead to tripping of some mills in service.
tripping is due to high bearing temp.
Boiler has tripped.
Lub. Oil pressure may be very low.
It will lead to tripping of some mills in service.
10.AIR PRE-HEATER
AIR PRE HEATER BEARING TEMPERATURE VERY HIGH.
AIR PRE-HEATER ELECTRIC MOTOR TRIPPED.
APH ELECTRIC DRIVE TRIPPED AND AIR MOTOR FAILS TO START.
AIR PRE-HEATER ON FIRE.
AIR PRE HEATER BEARING TEMPERATURE VERY HIGH.
AIR PRE-HEATER ELECTRIC MOTOR TRIPPED.
APH ELECTRIC DRIVE TRIPPED AND AIR MOTOR FAILS TO START.
AIR PRE-HEATER ON FIRE.
11.DRUM LEVEL LOW
Mal-operation of Feed Auto Control or Feed Regulator or scoop auto.
Tripping of one of working feed pump (standby pump does not start)
Sudden increase of load.
Sudden increase in firing rate, e.g.
starting of mills having sufficient coal left before previous stopping.
Tube repture/puncture of low point drain valves or Emergency drum drain Valve
Inadvertant opening of low point drain valves or Emergency drum drain valve.
Mal-operation of Feed Auto Control or Feed Regulator or scoop auto.
Tripping of one of working feed pump (standby pump does not start)
Sudden increase of load.
Sudden increase in firing rate, e.g.
starting of mills having sufficient coal left before previous stopping.
Tube repture/puncture of low point drain valves or Emergency drum drain Valve
Inadvertant opening of low point drain valves or Emergency drum drain valve.
12.HIGH DRUM LEVEL
Mal-operation of feed water control.
Sudden decrease in firing rate e.g. tripping of the running mills.
B.F.P. Scoop tube position suddenly increased.
Mal-operation of feed water control.
Sudden decrease in firing rate e.g. tripping of the running mills.
B.F.P. Scoop tube position suddenly increased.
13.FLAME FAILURE AT AN ELEVATION
Closing of trip valves on H.O. , W.U. Oil/ Ignitor (Causing loss of ignition support energy) Where F.O. is being used as support fuel or when only oil is being used
Sudden decrease of mill feeder speeds to minimum.
Too low or too high windbox pressure causing unstable combustion.
Water wall tube failure
Malfunction of flame scanners due to supply failure or scanner air failure,
slag or soot on scanner lenses etc.
Burner tilt mechanism negative extreme due to air failure to power cylinders.
Closing of trip valves on H.O. , W.U. Oil/ Ignitor (Causing loss of ignition support energy) Where F.O. is being used as support fuel or when only oil is being used
Sudden decrease of mill feeder speeds to minimum.
Too low or too high windbox pressure causing unstable combustion.
Water wall tube failure
Malfunction of flame scanners due to supply failure or scanner air failure,
slag or soot on scanner lenses etc.
Burner tilt mechanism negative extreme due to air failure to power cylinders.
14.ONE FEEDER TRIPS
Support energy is removed within 3 minutes of feeder starting.
No coal flow alarm comes & low current relay picks up simultaneously.
(Feeder shear pin given way)
Mill trips,
Feeder motor supply fails
Support energy is removed within 3 minutes of feeder starting.
No coal flow alarm comes & low current relay picks up simultaneously.
(Feeder shear pin given way)
Mill trips,
Feeder motor supply fails
15.Mill discharge valves are closed
Loss of elevation D.C. supply for more than 2 secs.
Support ignition energy is removed Within 3 minutes of feeder starting.
Motor protection operates.
One P.A. Fan trips (mill in excess of 3 will trip starting from bottom).
Loss of elevation D.C. supply for more than 2 secs.
Support ignition energy is removed Within 3 minutes of feeder starting.
Motor protection operates.
One P.A. Fan trips (mill in excess of 3 will trip starting from bottom).
16.WATER MILL TUBE LEAKAGE
Starved water walls due to very low drum level.
Sustained flame impingement on water wall tubes.
Blocked tube, scaling of tube, resulting in overheating of tube metal, pitting, corrosion of tubes.
Soot blower steam impingement (wet steam impingement or direct impingement of steam).
Circulation affected due to opening of low point drains.
Starved water walls due to very low drum level.
Sustained flame impingement on water wall tubes.
Blocked tube, scaling of tube, resulting in overheating of tube metal, pitting, corrosion of tubes.
Soot blower steam impingement (wet steam impingement or direct impingement of steam).
Circulation affected due to opening of low point drains.
17.REHEATER/SUPFRHEATER/ ECONOMISER TUBE FAILURE
Sustained high metal temperatures due to waterwall Slagging or forcing boiler at the time of hot restart.
Erosion on tubes due to high excess air, high ash content in coal dislocated tubes, soot blowing.
Blocked tubes causing overheating.
Salt deposition due to high water level in drum, poor quality of water.
Inadequate flow due to open superheater, reheater drain.
Sustained high metal temperatures due to waterwall Slagging or forcing boiler at the time of hot restart.
Erosion on tubes due to high excess air, high ash content in coal dislocated tubes, soot blowing.
Blocked tubes causing overheating.
Salt deposition due to high water level in drum, poor quality of water.
Inadequate flow due to open superheater, reheater drain.
18.Problem in Bottom Ashing System
Continuous watch on ash build up
Reduce load
Stopping of unit
Continuous watch on ash build up
Reduce load
Stopping of unit
19.TURBINE
20.TURBINE EMERGENCIES
SUDDEN LOAD THROW OFF
SUDDEN INCREASE OF LOAD FROM FULL LOAD
VIBRATION HIGH
TURBINE OVER SPEED
MOT LEVEL LOW
TURBINE BEARING OIL PRESS LOW
BEARING OIL INLET TEMP. HIGH
DIFFERENTIAL EXPANSION HI/LOW
AXIAL SHIFT HIGH
LOSS OF VACUUM
LOSS OF BARRING GEAR OR BARRING GEAR FAILS TO START
SUDDEN LOAD THROW OFF
SUDDEN INCREASE OF LOAD FROM FULL LOAD
VIBRATION HIGH
TURBINE OVER SPEED
MOT LEVEL LOW
TURBINE BEARING OIL PRESS LOW
BEARING OIL INLET TEMP. HIGH
DIFFERENTIAL EXPANSION HI/LOW
AXIAL SHIFT HIGH
LOSS OF VACUUM
LOSS OF BARRING GEAR OR BARRING GEAR FAILS TO START
21.HOTWELL LEVEL LOW
Excessive flow to D/A from Hotwell
Some leakage in steam/water (feed) circuit (water-wall super heater, Economiser etc.).
ACS Xmitter failure/fault.
DM make-up may be inadequate.
DM make up pump may have tripped.
Excessive flow to D/A from Hotwell
Some leakage in steam/water (feed) circuit (water-wall super heater, Economiser etc.).
ACS Xmitter failure/fault.
DM make-up may be inadequate.
DM make up pump may have tripped.
22.Malfunctioning of condensate PP valve
Malfunctioning of DM make up valve.
Condenser tube leakage
Too much DM make-up to Hotwell.
Hotwell set point too high.
ACS transmitter fault.
Condensate pumps may have tripped
Malfunctioning of DM make up valve.
Condenser tube leakage
Too much DM make-up to Hotwell.
Hotwell set point too high.
ACS transmitter fault.
Condensate pumps may have tripped
23.Steam ejector not properly functioning.
High level in condenser
LOSS OF CIRCULATING WATER PUMP
Air leak into system
Condenser tube choking
CW inlet water temp hi.
High level in condenser
LOSS OF CIRCULATING WATER PUMP
Air leak into system
Condenser tube choking
CW inlet water temp hi.
24.BOILER FEED PUMP
BFP RE-CIRCULATION VALVE FAILS CLOSED.
BFP LOSS OF LUB. OIL PRESSURE
BFP BEARING VIBRATION HIGH
BFP HYDRAULIC COUPLING OUTLET OIL TEMPERATURE IS GOING HIGH.
BFP SUCTION PRESSURE IS FALLING LOW.
BOILER FEED PUMP MASTER SPEED CONTROLLER FAILS HIGH.
BFP RE-CIRCULATION VALVE FAILS CLOSED.
BFP LOSS OF LUB. OIL PRESSURE
BFP BEARING VIBRATION HIGH
BFP HYDRAULIC COUPLING OUTLET OIL TEMPERATURE IS GOING HIGH.
BFP SUCTION PRESSURE IS FALLING LOW.
BOILER FEED PUMP MASTER SPEED CONTROLLER FAILS HIGH.
25.GENERATOR
26.Generator emergencies
Stator Water Flow Low
Stator Water Conductivity High
Hydrogen Pressure Low/Hydrogen leakage
Hydrogen Purity Low
Seal Oil Differential pr low
Liquid in Generator
Generator Stator Cooling Water Leakage
Damper Tank Level Low
Rotor Temperature High
Stator Winding Temperature High
Loss of Excitation
Generator Transformer Cooling System Trouble
Generator Rotor Earth Fault.
Stator Water Flow Low
Stator Water Conductivity High
Hydrogen Pressure Low/Hydrogen leakage
Hydrogen Purity Low
Seal Oil Differential pr low
Liquid in Generator
Generator Stator Cooling Water Leakage
Damper Tank Level Low
Rotor Temperature High
Stator Winding Temperature High
Loss of Excitation
Generator Transformer Cooling System Trouble
Generator Rotor Earth Fault.
27.GRID FAILURE
1.DC lighting ON ( Torch light must be available at least in night shift).
2. Ensure starting of emergency DC drives:
-Gen Seal Oil pump.
-LOP of main TG
-Scanner air fan.
Then monitor battery voltage and current.
3. Ensure starting of air motors of APH’s.
4. Open vacuum breaker manually.
Close MOT oil centrifuge supply vv.
Close SB isolation vv.
Close gland steam supply vv.
1.DC lighting ON ( Torch light must be available at least in night shift).
2. Ensure starting of emergency DC drives:
-Gen Seal Oil pump.
-LOP of main TG
-Scanner air fan.
Then monitor battery voltage and current.
3. Ensure starting of air motors of APH’s.
4. Open vacuum breaker manually.
Close MOT oil centrifuge supply vv.
Close SB isolation vv.
Close gland steam supply vv.
28.5.Ensure starting of DG set ,charging of EMCC and then changing over of emergency drives.
6.Open the incomer breakers of switch gears and transformers (motor breakers tripped on no voltage ).
7.After normalization of EMCC TVDC,BVDC AND BDDC power supply will restore. So care must be taken so that condenser/FT etc. will not
29.MISCELLANEOUS SYSTEMS
LOSS OF STATION AIR PRESSURE.
LOSS OF INSTRUMENT AIR PRESSURE.
BOILER WATER SILICA HIGH.
ELECTRICAL TRIPPING OF SUPPLY TO THE BOARD.
6.Open the incomer breakers of switch gears and transformers (motor breakers tripped on no voltage ).
7.After normalization of EMCC TVDC,BVDC AND BDDC power supply will restore. So care must be taken so that condenser/FT etc. will not
29.MISCELLANEOUS SYSTEMS
LOSS OF STATION AIR PRESSURE.
LOSS OF INSTRUMENT AIR PRESSURE.
BOILER WATER SILICA HIGH.
ELECTRICAL TRIPPING OF SUPPLY TO THE BOARD.
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