1.2.2- 9HA GE Gas Turbine Lubrication Oil System

9 HA GE Gas Turbine Lubrication Oil System

2.4 Heat Exchanger and Filters:

The lubricant oil heat exchangers(LOHX-1 and LOHX-2) connect o the parallel lubricant filters(LF3-1 and LF3-2) This design is provided so that filters not in service can be changed without taking the turbine out of service.

Filter housings and heat exchangers are self-venting. A sight glass is located in the vent line from e filter and heat exchanger. When the heat exhanger and filter housing are full, oil will be visible in this sight glass.

By means of the manually-operated three-way transfer valve, one filter can be put into service as the second is taken out, without interrupting the oil flow to the main lube oil header. The transfer of operation from one filter to the other should be accomplished as follows:

1.           Close the drain valve of the filter. Open the filter valve and fill the standby filter until a solid oil flow can be seen in the flow sight in filter vent pipe. This will indicate a “filled” condition.
2.            Operate the transfer valve to bring the standby filter into service.
3.          Close the filler valve.                                                                                                                   

This procedure simultaneously brings the reserve heat exchanger into service.

Note

Only one heat exchanger is intended to be in service at one time. After transfer, the operator must verify that the cooling water isolation butterfly valves to/from the heat exchanger not in service are closed. Do not leave all four cooling water isolation valves open.

2.5 Seal Oil

The seal oil to the generator bearing is normally supplied by the lubricating system by the lubricating system through a separate line directly to the generator in the event of low lube system pressure or lube system shutdown for service one of two seal oil pumps supply the oil required to seal in the generator hydrogen. Under normal circumstances the AC motor driven pump would serve this function however if this AC motor should fail or if AC power is lost the emergency DC motor is activated and drives the seal oil pump in piggyback AC/DC motor configuration separated AC and DC pumps). The AC motor includes a heater to prevent condensation in the motor. The seal oil pumps circulate oil through filter. Differential pressure switch provides a high differential pressure alarm signal across the filter. The filter element should be replaced near or at the alarm set point.

2.6 Optional Devices

Pressure transmitters

The lubrication module may include the following additional pressure transmitters (indication only) when selected by a customer as an option;

1.      Differential pressure transmitters which provide remote monitoring capability of differential pressure across oil filters.

2.       Pressure transmitter which provides remote monitoring capability of bearing header pressure.

3.       Pressure which provides remote monitoring capability of tank oil level.

These transmitters are indication only devices. They do not alarm or trio the machine in case of failure, low pressure, level etc.

Lube Oil Conditioner

The lube oil system may also include a lube oil conditioner when selected by a customer as an option. The lube oil conditioner is a stand-alone, kidney-loop lube oil conditioning skid designed specifically to remove particulate contamination (from 0.2 to 2 microns in size). Particulate contamination in this size range is the precursor to varnish formation and accumulation. The implementation of lube oil condition together with monitoring and maintenance of the lubrication oil additive package will help prevent the formation and accumulation of varnish and therefore varnish related turbine trips due to sticking hydraulic servo valves etc.) The lube oil condition skid is a standalone customer located skid with all function controlled by an onboard PLC there is no interface to MK VI control system.

Oil entering the Lube oil conditioner skid is monitored for temperature via thermocouple LT-LC. The oil then passes through the pump and into the pre-filter which is monitored for pressure by transducer. The oil then passes into the charging/mixing vessel, which is monitored for pressure by a transducer. Next, the oil moves to the final canister, containing the post-filter which is monitored for pressure by transducer. Finally, oil exiting the skid is monitored for pressure by transducer. All of these devices communicate solely with the PLC onboard the Lube Oil Conditioner Skid.