TURBINE BARRING GEAR / TURNING GEAR OPERATION
Hot turbine rotor and generator shaft is slowly rotated for uniformly cooing down rotor shafts to avoid distortion or bending. Also its operation is used when Turbine generator rotor is shut down for a prolonged period. In cold turbine periodic turning gear operation is used to rotate shaft position so that because of rotor weight hanging at bearings do not deform downwards at its centre of gravity.
Jack oil system
Turbine &Generator rotor is slightly lifted from its bearing position to reduce the starting torque requirement to rotate rotor at its initial running moment. A positive displacement pump of High pressure is used to supply oil to bearings to jack the rotor system.
Turbine Lube oil requirement
Turbine bearings are force lubricated system, in which lubricating oil is forced into the bearings to maintain lubrication requirement between static and rotating parts of bearings. Lubricating oil pump(s) are separately mounted to a lubricating oil tank which pumps oil to bearings and which is re circulated by suitable oil piping system, and its accessories. Hot oil after lubrication returns to tank which passes through a oil cooler to reduce oil temperature and again used in bearings. Suitable oil filters, suction filters, Oil injectors are the necessary arrangements to fulfill the systems certain needs of oil purifications, positive oil supply to pump suction, which is as discussed hereunder.
One oil pump (MOP) is either directly mounted or through gear arrangement at the turbine generator rotor system is used. When turbine attains its rated speed around 85% it started pumping lubricating oil in the system instead of the one placed outside(AOP), thus reducing power consumption.
As both these pump also supplies oil to Hydraulic speed control mechanism of Turbine to main Power frequency and in turn Generator Power Control system, these pumps Head development and Capacity delivered are bigger as compared to Emergency lubrication system pump(s)
Emergency Lubrication System
When in any case AC supply of the Force lubricating pump(AOP) is not available or any breakdown occurrence of the pumping unit another DC motor driven pump is used as Emergency Oil Pump which starts and starts supply of Lubricating Oil to bearings. This is an emergency measure and suitably incorporated in the system for automatic start
Over Head Oil Tank
This is also an emergency measure of Lube oil supply to bearings in which lubricating oil is continuously stored in a overhead mounted oil tank which can supply oil by gravity to bearings in case both pumps fails to supply lube oil in the rotating shaft.
Preparation of LUBE OIL SYSTEM prior to start of LUBE OIL CIRCUIT
1. Main oil tank is to be filled up with proper grade and quality of lube oil up to its optimum level as when Pump will be in service in can fill up Overhead Oil Tank also without shortfall of AOP or MOP pumping need.
2. Open Suction valve of AOP/MOP (if any)
3. Close Discharge Valve of AOP
4. Chose any one of the lube oil cooler for service by suitably opening of lube oil coolers inlet and outlet valve fully.
5. Choose any one of the duplex filter for service by suitably opening its inlet and outlet valve or changeover valve position.
6. Bearing inlet valves should be accurately opened for individual all bearings lube oil requirement, which varies.
7. Control Oil system is to be lined up by opening its isolation valve.
8 . Check all piping systems for any looseness, deformations, supporting system etc. thoroughly
9. Lineup Over head Oil tank system and its return piping circuit to bearings,
10. Open all pressure gauges impulse line, temperature gauges are working, Pressure , temperature transmitters , switches are properly working condition with all permissive, interlocks, protection circuit through DCS system.
11. Emergency Oil pump system DC Power, Battery system, Battery charger, Inverter, converter unit are healthy working condition.
10. Open Emergency DC Oil pump Suction valve
11. Close Emergency oil pump Discharge valve
12. Start Emergency Oil Pump
13. Open Discharge valve
14. After ensuring bearing oil flows are normal with pressure gauges are normal working , Pressure transmitter is showing Lube oil header pressure, Lube oil temperature are showing at local and DCS and no leakages are there, in the system.
15. Start AOP, and Open discharge valve
16. Oil header pressure will show through Local and DCS system
17. Check Overhead tank oil supply and its return.
17. All permissive are available except jack oil Pump pressure to start barring gear.
18. Line Jack oil pump discharge valves to bearings and pump discharge valve .
19. Jack Oil pump power supply is healthy
20. Start Jack oil Pump.
21. Ensure Barring Gear start permissive is available.
22. Slowly turn barring gear by hand wheel to engage its clutch mechanism and ensure Turbine freeness
23. Start barring gear, check barring current and record, Record Vibration and bearing oil pressure.
24. Main Oil temperature by adjusting cooling water supply to oil coolers. 42Deg C
Hot turbine rotor and generator shaft is slowly rotated for uniformly cooing down rotor shafts to avoid distortion or bending. Also its operation is used when Turbine generator rotor is shut down for a prolonged period. In cold turbine periodic turning gear operation is used to rotate shaft position so that because of rotor weight hanging at bearings do not deform downwards at its centre of gravity.
Jack oil system
Turbine &Generator rotor is slightly lifted from its bearing position to reduce the starting torque requirement to rotate rotor at its initial running moment. A positive displacement pump of High pressure is used to supply oil to bearings to jack the rotor system.
Turbine Lube oil requirement
Turbine bearings are force lubricated system, in which lubricating oil is forced into the bearings to maintain lubrication requirement between static and rotating parts of bearings. Lubricating oil pump(s) are separately mounted to a lubricating oil tank which pumps oil to bearings and which is re circulated by suitable oil piping system, and its accessories. Hot oil after lubrication returns to tank which passes through a oil cooler to reduce oil temperature and again used in bearings. Suitable oil filters, suction filters, Oil injectors are the necessary arrangements to fulfill the systems certain needs of oil purifications, positive oil supply to pump suction, which is as discussed hereunder.
One oil pump (MOP) is either directly mounted or through gear arrangement at the turbine generator rotor system is used. When turbine attains its rated speed around 85% it started pumping lubricating oil in the system instead of the one placed outside(AOP), thus reducing power consumption.
As both these pump also supplies oil to Hydraulic speed control mechanism of Turbine to main Power frequency and in turn Generator Power Control system, these pumps Head development and Capacity delivered are bigger as compared to Emergency lubrication system pump(s)
Emergency Lubrication System
When in any case AC supply of the Force lubricating pump(AOP) is not available or any breakdown occurrence of the pumping unit another DC motor driven pump is used as Emergency Oil Pump which starts and starts supply of Lubricating Oil to bearings. This is an emergency measure and suitably incorporated in the system for automatic start
Over Head Oil Tank
This is also an emergency measure of Lube oil supply to bearings in which lubricating oil is continuously stored in a overhead mounted oil tank which can supply oil by gravity to bearings in case both pumps fails to supply lube oil in the rotating shaft.
Preparation of LUBE OIL SYSTEM prior to start of LUBE OIL CIRCUIT
1. Main oil tank is to be filled up with proper grade and quality of lube oil up to its optimum level as when Pump will be in service in can fill up Overhead Oil Tank also without shortfall of AOP or MOP pumping need.
2. Open Suction valve of AOP/MOP (if any)
3. Close Discharge Valve of AOP
4. Chose any one of the lube oil cooler for service by suitably opening of lube oil coolers inlet and outlet valve fully.
5. Choose any one of the duplex filter for service by suitably opening its inlet and outlet valve or changeover valve position.
6. Bearing inlet valves should be accurately opened for individual all bearings lube oil requirement, which varies.
7. Control Oil system is to be lined up by opening its isolation valve.
8 . Check all piping systems for any looseness, deformations, supporting system etc. thoroughly
9. Lineup Over head Oil tank system and its return piping circuit to bearings,
10. Open all pressure gauges impulse line, temperature gauges are working, Pressure , temperature transmitters , switches are properly working condition with all permissive, interlocks, protection circuit through DCS system.
11. Emergency Oil pump system DC Power, Battery system, Battery charger, Inverter, converter unit are healthy working condition.
10. Open Emergency DC Oil pump Suction valve
11. Close Emergency oil pump Discharge valve
12. Start Emergency Oil Pump
13. Open Discharge valve
14. After ensuring bearing oil flows are normal with pressure gauges are normal working , Pressure transmitter is showing Lube oil header pressure, Lube oil temperature are showing at local and DCS and no leakages are there, in the system.
15. Start AOP, and Open discharge valve
16. Oil header pressure will show through Local and DCS system
17. Check Overhead tank oil supply and its return.
17. All permissive are available except jack oil Pump pressure to start barring gear.
18. Line Jack oil pump discharge valves to bearings and pump discharge valve .
19. Jack Oil pump power supply is healthy
20. Start Jack oil Pump.
21. Ensure Barring Gear start permissive is available.
22. Slowly turn barring gear by hand wheel to engage its clutch mechanism and ensure Turbine freeness
23. Start barring gear, check barring current and record, Record Vibration and bearing oil pressure.
24. Main Oil temperature by adjusting cooling water supply to oil coolers. 42Deg C
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