Quick
troubleshooting guide for steam Turbines
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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