Steam Turbines - Operation -Part2

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B.  Sequence when the turbine is in motion:

1. Apply the load gradually.
2. Check up the oil pressure going to the bearings and control gear.
3. Observe the oil bearing temperature.
4. Observe the turbine for any noise, vibration by watching the vibration and other indicators.

C. Sequence when shutting the turbine down:

1. Gradually reduce the load to 0.
2. Start the auxiliary oil pump and make sure that oil will be supplied to bearings at proper pressure while the turbine is coming to a stop.
3. Trip the emergency valve.
4. Close the leak off from the H.P glands.
5. Stop the supply of cooling water to the condenser.
6. Shut down the condensing equipment and open drains on turbine pipings and casings.
7. Continue auxiliary oil pumps in operation untill the turbine rotor has stopped.
8. Operate turning gear to rotate rotor at about 3-30 rpm for some time.

During operation, it is good practice to keep a log sheet and record the hourly readings of the instruments. Some of the readings which might prove valuable are the following:

Load on the generator throttle, steam pressure and temperature, exhaust pressure, temperature of cooling water entering and leaving the cooler, bearing oil pressure and temperature, the throttle steam flow rate, speed, frequency, vibration level.

The main requirement of steam turbine while in operation are the proper application of oil to the bearings and a continuous flow of cooling water.

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Also read:
Construction of Steam Turbines
Maintenance of Steam Turbines