Main Equipments Tripped





S.No
Fault
Consequence
Actions


1


1 mill Tripped out of 6
Ø  Runback will Act
Ø  Capability - 466 MW
Ø  Machine Comes in IP mode
Ø  Reduce Load
Ø  Observe Drum Level( will go up)
Ø  Reduce Throttle Pressure SP
Ø  Take another Mill



2



2 mills Tripped out of 6
Ø  Runback will Act
Ø  Capability - 372 MW
Ø  Machine Comes in IP mode
Ø  Reduce Load
Ø  Observe Drum Level( will go up)
Ø  Observe Flame Scanner
Ø  If Necessary take Oil gun at an elevation
Ø  Reduce Throttle Pressure SP
Ø  Take another Mill
3
Any one ID Fan Trips
Ø  Runback will Act
Ø  Unit Capability-300 MW
Ø  Trip command to Respective FD Fan/ If not Tripped, Trip FD
Ø  Only 5 mills will Remain , rest will trip from top/ If not tripped, Trip from top leaving only 5 mills
Ø  Machine Comes in IP Mode
Ø  Observe Furnace Pressure
Ø  Observe Total Air Flow
Ø  Ensure Tripped FD Discharge Damper Closed
Ø  Ensure running FD Fan current in limit
Ø  Ensure Tripped ID Fan IGV closed on auto
Ø  Observe Drum Level
Ø  Observe Scanner
Ø  Reduce throttle Pr SP
Ø  Inform Maintenance for check
4
Both ID Fans Tripped
Ø  Unit will trip on MFT
Ø  Do shutdown Activities






5






Any one FD Fan Trips
Ø  Runback will Act
Ø  Unit Capability-300 MW
Ø  Trip command to Respective ID Fan/ If not Tripped, Trip ID
Ø  Only 5 mills will Remain , rest will trip from top/ If not tripped, Trip from top leaving only 5 mills
Ø  Machine Comes in IP Mode
Ø  Observe Furnace Pressure
Ø  Observe Total Air Flow
Ø  Ensure Tripped FD Discharge Damper Closed
Ø  Ensure running FD Fan current in limit
Ø  Ensure Tripped ID Fan IGV closed on auto
Ø  Observe Drum Level
Ø  Observe Scanner
Ø  Reduce throttle Pr SP
Ø  Inform Maintenance for check
4
Both FD Fans Tripped
Ø  Unit will trip on MFT
Ø  Do shutdown Activities






5






Anyone PA Fans Trip
Ø  Unit Capability-300 MW
Ø  If PA Header comes to 625 mmWC and not increased within 5 Seconds, all Mills will Trip on PA Header Pressure Low and Unit will trip on Loss of All Fuel
Ø  If PA Header comes to 500 mmWC, all Mills will Trip on PA Header Pressure Low and Unit will trip on Loss of All Fuel
Ø  Observe PA Header Pressure
Ø  Ensure Discharge Damper of PA Fan got closed
Ø  Observe Drum, Furnace, Total air flow
Ø  Observe Flame Scanner, Take Oil gun in elevation if required
Ø  Inform concerned Department for Tripping of Fan

4

Both PA Fans Tripped
Ø  all Mills will Trip on PA Header Pressure Low and Unit will trip on Loss of All Fuel(MFT)
Ø  Do shutdown Activities



5



Any1 BCW trips out of 2
Ø  Standby will come
Ø  If standby BCW pump do not come, runback will Act
Ø  Capability- 300 MW
Ø  Only 5 mills will Remain , rest will trip from top/ If not tripped, Trip from top leaving only 5 mills
Ø  Inform Concerned /department for the Tripping
Ø  Observe Drum level
Ø  Observe Flame Scanner
Ø  Observe running Pump DP

6

2 BCW pumps Trip
Ø  Standby BCW will come
Ø  Runback will Act
Ø  Only 5 mills will Remain , rest will trip from top/ If not tripped, Trip from top leaving only 5 mills
Ø  If standby donot come, Boiler will trip on MFT due to Waterwall Circulation Incorrect
Ø  Observe Drum,Furnace, BCW DP, flame Scanner
Ø  If unit trips, Follow the shutdown activities




7




Anyone SAPH Trips
Ø  Air Motor Comes in auto
Ø  If air Motor do not come, runback will act
Ø  Capability:300 MW
Ø  Only 5 mills will Remain , rest will trip from top/ If not tripped, Trip from top leaving only 5 mills
Ø  Observe SAPH FG /Air Outlet Temperature
Ø  Inform concerned deptt for Tripping of SAPH
Ø  If air Motor does not come , Ensure Closing of SAPH FG & Air Inlet & Outlet dampers
Ø  Observe Secondary air temperature at Windbox inlet




8




Both SAPH Trips
Ø  Air motor comes in auto



Ø  Air motor do not come, Unit will trip on Both SAPH Tripped (MFT)
Ø  Observe SAPH FG /Air Outlet Temperature
Ø  Inform concerned deptt for Tripping of SAPH
Ø  If air motor do not come, Follow the shutdown activities





9





Anyone SAPH Trips
Ø  Air Motor Comes in auto




Ø  If air Motor do not come,
Ø  Observe PAPH FG /Air Outlet Temperature
Ø  Inform concerned deptt for Tripping of SAPH

Ø  Ensure Closing of PAPH FG & Air Inlet & Outlet dampers
Ø  Observe PAPH FG /Air Outlet Temperature
Ø  Reduce load to 300 MW
Ø  Keep 4/5 Mills in service
Ø  Observe Mill Outlet temp






10






Both PAPH Trips
Ø  Air Motor Comes in auto




Ø  If air Motor do not come,
Ø  Observe PAPH FG /Air Outlet Temperature
Ø  Inform concerned deptt for Tripping of SAPH

Ø  Try to restore at least one PAPH
Ø  Take Maximum Oil guns
Ø  Stop All Mills One by One, Stop PA Fan
Ø  Observe Furnace Pr, Total air Flow, Reduce Throttle Pr SP
Ø  Take MDBFP & Maintain Drum Level
Ø  Load May get stabilized at 100 MW






11






Anyone TDBFP Trips
Ø  MDBFP will come in auto



Ø  MDBFP do not come in 10 seconds, Runback will Act
Ø  Unit Capability: 270 MW
Ø  Only 4 mills will remain
Ø  Machine will come in IP mode
Ø  MDBFP R/C Valve close on Auto, If not Close it
Ø  Inform Concerned Deptt

Ø  Ensure running TDBFP in auto, Drum Level in auto. Otherwise Increase Speed Reference
Ø  Observe Difference b/w BLI and FW, If its still High, Reduce Coal flow
Ø  Still Drum is not Rising, Trip 1 mill and take one oil gun
Ø  Reduce Th Pr SP
Ø  Inform concerned  Deptt
12
Both TDBFP trips
Ø  MDBFP comes in Auto
Ø  Only 4 mills remains
Ø  Machine comes in IP Mode
Ø  Increase MDBFP Scoop to maintain Drum Level. Close its r/c valve
Ø  Still Drum is not Rising, Trip 1 mill and take one oil gun
Ø  Reduce Th Pr SP
Ø  Inform concerned  Deptt


13


Both TDBFP Trips
Ø  MDBFP does not come in auto
Ø  Unit will trip on MFT(No BFP)
Ø  Do shutdown activities
Ø  Inform concerned Deptt





14





Any 1 CEP Trips
Ø  Standby CEP comes in auto

Ø  If  standby does not come , runback will act, Capability: 275 MW
Ø  Only 5 mills will Remain , rest will trip from top/ If not tripped, Trip from top leaving only 5 mills
Ø  Machine comes in IP Mode
Ø  Inform concerned Deptt

Ø  Close D/A CV to raise CEP discharge Header Pr
Ø  Observe D/A level
Ø  Reduce Pressure SP








15








Both CEP Trips
Ø  Standby CEP comes in auto
Ø  Only 5 mills will Remain , rest will trip from top/ If not tripped, Trip from top leaving only 5 mills
Ø  Machine comes in IP Mode


Ø  Standby CEP does not come in auto
Ø  Only 5 mills will Remain , rest will trip from top/ If not tripped, Trip from top leaving only 5 mills
Ø  Machine comes in IP Mode
Ø  Close D/A CV to raise CEP discharge Header Pr
Ø  Observe D/A level
Ø  Reduce Pressure SP




Ø  Try to restore at least one CEP
Ø  Trip Mills one by one & Reduce load < 100 MW
Ø  Take one/two elevation guns
Ø  Observe D/A , H/W and Vacuum
Ø  Take MDBFP to maintain Drum
Ø  Unit May trip on D/A Level Low, Vacuum if any of the CEPs cannot be revived


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