power point presentation 40
TRANSCRIPT
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POWER PLANTEMERGENECIES
Manoj Barsaiyan
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BOILER
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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. orflue gas path manhole opened.
Water wall tube rupture/leakage.
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ID FAN LUB. OIL PRESSURE /
BEARING TEMP TROUBLE Lub. oil pressure may be inadequate.
Lub. oil filters may be choked.
Greasing long overdue in fanbearings.
Corresponding alarm will indicate the
problem area.
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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.
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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 millsor choking of mill/raw coal Feederpipe.
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FD FAN TRIPPED
Motor over-loaded
Lub oil pressure trouble.
Bearing temperature trouble. ID fan has tripped.
FD lub. Oil pressure low.
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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.
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AIR PRE-HEATER
AIR PRE HEATER BEARINGTEMPERATURE VERY HIGH.
AIR PRE-HEATER ELECTRIC MOTORTRIPPED.
APH ELECTRIC DRIVE TRIPPED ANDAIR MOTOR FAILS TO START.
AIR PRE-HEATER ON FIRE.
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DRUM LEVEL LOW
Mal-operation of Feed Auto Control or Feed Regulatoror scoop auto.
Tripping of one of working feed pump (standby pumpdoes not start)
Sudden increase of load.
Sudden increase in firing rate, e.g.
starting of mills having sufficient coal left beforeprevious 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.
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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.
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FLAME FAILURE AT ANELEVATION
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 beingused
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 airfailure to power cylinders.
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ONE FEEDER TRIPS
Support energy is removed within 3minutes of feeder starting.
No coal flow alarm comes & lowcurrent relay picks up simultaneously.
(Feeder shear pin given way)
Mill trips, Feeder motor supply fails
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ONE MILL TRIPS
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).
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WATER MILL TUBE LEAKAGE
Starved water walls due to very low drumlevel.
Sustained flame impingement on water wall
tubes. Blocked tube, scaling of tube, resulting inoverheating of tube metal, pitting,corrosion of tubes.
Soot blower steam impingement (wet
steam impingement or direct impingementof steam). Circulation affected due to opening of low
point drains.
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REHEATER/SUPFRHEATER/ECONOMISER TUBE FAILURE
Sustained high metal temperatures due towaterwall Slagging or forcing boiler at thetime 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.
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Problem in Bottom Ashing System Continuous watch on ash build up
Reduce load
Stopping of unit
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TURBINE
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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 GEARFAILS TO START
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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.
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HOTWELL LEVEL HIGH.
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
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LOSS OF VACUUM
Steam ejector not properlyfunctioning.
High level in condenser LOSS OF CIRCULATING WATER PUMP
Air leak into system
Condenser tube choking CW inlet water temp hi.
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BOILER FEED PUMP
BFP RE-CIRCULATION VALVE FAILSCLOSED.
BFP LOSS OF LUB. OIL PRESSURE
BFP BEARING VIBRATION HIGH
BFP HYDRAULIC COUPLING OUTLET OILTEMPERATURE IS GOING HIGH.
BFP SUCTION PRESSURE IS FALLING LOW. BOILER FEED PUMP MASTER SPEED
CONTROLLER FAILS HIGH.
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GENERATOR
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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.
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GRID FAILURE1.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 ofair motors of APHs.
4.Open vacuum breaker manually. Close MOT oil centrifuge supply vv.
Close SB isolation vv.
Close gland steam supply vv.
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GRID FAILURE5.Ensure starting ofDG set ,charging of
EMCC and then changing over ofemergency drives.
6.Open the incomer breakers of switchgears and transformers (motorbreakers tripped on no voltage ).
7.After normalization of EMCC TVDC,BVDCAND BDDC power supply will restore.So care must be taken so thatcondenser/FT etc. will not
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MISCELLANEOUS SYSTEMS
LOSS OF STATION AIR PRESSURE.
LOSS OF INSTRUMENT AIR
PRESSURE. BOILER WATER SILICA HIGH.
ELECTRICAL TRIPPING OF SUPPLY TOTHE BOARD.
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THANK YOU