Mastodon Power plant and calculations: Quick troubleshooting guide for steam Turbines.

Quick troubleshooting guide for steam Turbines.

                           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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