|
SL No.
|
Problem
|
Root cause
|
Remedy/Action to
be taken
|
|
1
|
High bearing vibrations
|
High lube oil
temperature
|
Maintain normal lube
oil temperature 40-42 deg C or as per OEM recommendations
|
|
More clearance in
bearing
|
Maintain bearing
clearance within the limit as recommended by OEM
|
|
Contaminants/burs in
oil
|
1.Ensure oil
centrifuge is in service and is running in clarification mode
2.Get tested the oil
parameters yearly and ensure all parameters are within limit
|
|
Over load operation
|
Operate the Turbine
at or within its maximum capacity
|
|
Malfunction of the
vibration sensor
|
Get confirm the high
bearing vibrations are due to malfunction, if confirmed ensure tightness of
all connections.
|
|
2
|
High bearing temperature
(Journal)
|
High lube oil
temperature
|
Maintain normal lube
oil temperature 40-42 deg C or as per OEM recommendations
|
|
Low lube oil
pressure
|
Maintain correct
lube oil pressure at all bearing inlet
|
|
Over load operation
|
Operate the Turbine
at or within its maximum capacity
|
|
Less clearance in
bearing
|
Maintain bearing
clearance within the limit as recommended by OEM
|
|
Malfunction of the temperature
sensor
|
Get confirm the high
bearing vibrations are due to malfunction, if confirmed ensure tightness of
all connections.
|
|
3
|
High bearing temperature
(Thrust)
|
High lube oil
temperature
|
Maintain normal lube
oil temperature 40-42 deg C or as per OEM recommendations
|
|
Low lube oil
pressure
|
Maintain correct
lube oil pressure at all bearing inlet
|
|
Operation of the
Turbine at more exhaust flow (Active side thrust side bearing temperature
will increase)
|
Operate the turbine
well within the designed/OEM recommended steam flow
|
|
Operation of the
Turbine at more extraction or bleed steam flow (Non-active side thrust
bearing temperature will increase)
|
Operate the turbine
well within the designed/OEM recommended steam flow
|
|
Improperly set Rotor
during overhauling
|
Rotor centring
should be corrected during overhauling
|
|
Malfunction of the temperature
sensor
|
Get confirm the high
bearing vibrations are due to malfunction, if confirmed ensure tightness of
all connections.
|
|
4
|
High axial displacement
|
Operation of the
Turbine at more extraction or bleed steam flow or exhaust flow
|
Operate the turbine
well within the designed/OEM recommended steam flow
|
|
5
|
Turbine Over speed/High speed
|
Sudden load
throw/off
|
Tuning governing system/actuator
to avoid over speeding of rotor during sudden load through off or trips
|
|
Improperly set
control valves
|
Proper setting of
control/throttle valves
|
|
ESV & HP-valves
Passing (Turbine rotor can go over speed if ESV does not close properly after
tripping of Turbine)
|
Servicing of
throttle (HP) valves & ESV during Turbine overhauling
|
|
Malfunction of
Governor and control system
|
Re-tuning of
Governor system
|
|
Stuck up of
control/throttle valves
|
Checking Burs &
foreign materials in control valves seating ensure no accumulation of dust
over there.
|
|
6
|
Turbine running at Low
vacuum/exhaust pressure
|
Condenser cooling
(MCWP) water flow/pressure low
|
Increase MCWP flow
and pressure
|
|
Low pressure of
ejector motive steam
|
Increase ejector
steam pressure & maintain ejector steam pressure as per OEM recommended
|
|
More Cooling water
temperature
|
1.Increase cooling
water flow
2.Increase CT fans
speed
3.Operate one more
CT fan of required
|
|
Gland sealing steam
pressure less
|
Increase gland steam
pressure & maintain as per OEM recommended.
Note: Worn out labyrinths’ seals may call for more
gland steam pressure than normal recommended
|
|
Operation of the
Turbine at more condensing load (Exhaust steam flow to condenser is more)
|
Reduce the exhaust
steam flow & operate the Turbine at optimum exhaust steam flow to
condenser
|
|
Worn out ejector
nozzles
|
Replacement of
ejector nozzles during shutdowns
|
|
Atmosphere air
ingress in condensate system
|
Check & Arrest
air ingress (Check all valves gland, flanges, pipe line flanges,
safety/relief valves, CEP strainer flanges)
|
|
Ejector condenser
tubes leakage
|
Check & replace
or plug the leaked tubes
|
|
Ejector vacuum steam
traps not working properly
|
Check the traps
& adjust steam flow properly. If required service the steam traps
|
|
7
|
Sudden drop of vacuum
|
MCWP trip/Cooling
water flow reduced
|
Start stand by pump
or increase the flow
|
|
Sudden increase in
condenser load/ More exhaust steam flow to condenser
|
Reduce turbine load
Increase cooling
water flow
Then normalise the
Turbine load
|
|
Ejector steam
pressure reduced
|
Increase &
maintain ejector steam pressure
|
|
Gland sealing steam
pressure reduced
|
Check gland sealing
steam control valve & normalise the steam pressure
|
|
Air ingress in
condensate system
|
Check possible
ingress points & arrest the leakages.
Potential points for Air ingress are;
1-Air ingress from
CEP suction strainer
2-Vacuum breaker
valves
3-Ejector
safety/relief valves
4-Glands &
flanges of valves
|
|
All the CT fans
tripped or stopped
|
Check & start
the fans
|
|
Vacuum breaker valve
open/malfunction/passing
|
Check the valve and
close properly
|
|
8
|
Hot well level rising
|
Sudden drop of
vacuum
|
Check the root cause
of vacuum drop ( MCWP pump trip or less cooling water flow, ejector steam
pressure low etc) and correct it.
|
|
CEP pump tripped
|
Ensure stand by pump
is in AUTO mode & has started immediately
|
|
Air lock in running
CEP
|
Check the reason for
air ingress
Prime the pump &
restart
|
|
Hot well level
control valve stuck or malfunction
|
Check & rectify
the valve issue
|
|
CEP to D/A control
valve stuck or malfunction
|
Check & rectify
the valve issue
|
|
9
|
Low hot well level
|
Sudden increase in
extraction steam flow
|
Reduce extraction
steam flow
|
|
Hot well level
control valve closed/stuck/malfunction
|
Check and open the
hot well level control valve
|
|
CEP to Deaerator
control valve stuck/mal function
|
Check and rectify
the issue
|
|
Sudden start of
stand by pump
|
Check and stop the
pump if not required
|
|
|
|
|
10
|
Low lube oil pressure
|
Running oil pump
tripped
|
Ensure stand by pump
is in AUTO mode & has started immediately
|
|
PRV stuck or
malfunction
|
Check & rectify
the valve issue
|
|
Oil leakage
|
Check & arrest
oil leakage
|
|
Air lock in running
pump
|
Start tart the stand
by pump if not started in AUTO and then prime the pump.
|
|
High lube oil
temperature
|
Maintain lube oil
temperature within normal limit (40-45 deg C)
|
|
Lube oil filter
clogged
|
Change over the oil
filter
Clean the filter
|
|
11
|
Low Control oil pressure
|
Running oil pump
tripped
|
Ensure stand by pump
is in AUTO mode & has started immediately
|
|
PRV stuck or
malfunction
|
Check & rectify
the valve issue
|
|
Oil leakage
|
Check & arrest
oil leakage
|
|
Air lock in running
pump
|
Start tart the stand
by pump if not started in AUTO and then prime the pump.
|
|
Control oil filter
clogged
|
Change over the oil
filter
Clean the filter
|
|
12
|
High lube oil temperature
|
Lube oil cooler
outlet valve throttled
|
Open the cooling
water outlet valve as per requirement
|
|
Less cooling water
flow to Oil cooler
|
Ensure oil cooler
inlet cooling water valve is open 100% & outlet valve is throttled as per
requirement
|
|
Less cooling water
flow or low ACWP pressure
|
Increase the cooling
water flow & pressure
|
|
Poor heat transfer
in oil cooler or tubes fouling
|
Tubes cleaning &
back wash
|
|
13
|
Turbine load/speed hunting
|
Variation in
extraction steam pressure
|
Maintain extraction
steam pressure & flow constant-Talk with end user or process steam.
|
|
Burs on actuator
spindles
|
Clean the actuator
shaft & Ensure oil purification unit is in service
|
|
Control oil pressure
fluctuation
|
Ensure accumulator
is healthy and its operating pressure is at least 85-90% of control oil
operating pressure.
|
|
Contamination in oil
|
Ensure oil
purification unit is in service.
|
|
Improper tuning of
governor
|
Tune the Governor
properly
|
|
Tightness in
actuator links/resistance in the movement of linkages
|
Clean &
lubricate the actuator linkages & ensure free movement
|
|
14
|
More specific steam consumption
of Turbine
|
Pressure &
Temperature of main steam are low
|
Maintain the correct
pressure & temperature
|
|
Low vacuum
|
Maintain the vacuum
on higher side
|
|
High exhaust
temperature
|
Maintain the exhaust
temperature in the range of 40-50 deg C or as per exhaust pressure
|
|
Operation of the
Turbine at lower/partial loads
|
Operate the Turbine
at higher loads or at full capacity
|
|
More clearance in
labyrinth seals
|
Maintain OEM
recommended clearance between rotor & casing during Turbine major
overhauling
|
|
More extraction
steam flow than recommended
|
Reduce the
extraction flow & maintain as per HMBD
|
|
More bleed steam
flow than recommended
|
Reduce the bleed
steam flow & maintain as per HMBD
|
|
15
|
High wheel chamber pressure
|
Scaling of rotor
blades
|
1-Maintain water and
steam quality as per design
2-Descaling of rotor
blades during Turbine overhauling
|
|
Less clearance in
labyrinth seals
|
Maintain OEM
recommended clearance between rotor & casing during Turbine major
overhauling
|
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