Lube oil system in turbine
The turbine is the continuous operating unit in a power plant. The lube oil system plays a major role in turbine and generator operation. The bearing of the turbine and generator is supplied with the lube oil throughout their lives even during running or ideal. The lube oil system consists of the following parts
- Lube oil tank
- Auxiliary oil pump (AOP)
- Auxiliary control oil pump(ACOP)
- Emergency oil pump (EOP)
- Vapour extractor pump
- Oil cooler
- Oil filters
- Overhead oil tank
- Hydraulic accumulator
Lube oil tank
Lube oil tank is the closed system that keeps on lubricating the turbine and generator, after the impact, it will carry the temperature and some other impurities they are removed in the later stage. The lube oil tank is provided with level protection to alert in case of low and high level. And lube oil has to be purified for a particular interval, it is carried out regularly in the industry.
Auxiliary oil pump
The AOP is used to lubricate the turbine and generator initial before startup. After the turbine start running after reaching the high pressure setpoint, the pump will get stopped. In auto mode pump will be start and stop by the pressure switch contact. With the respective pressure set point, the pump will be operating.
Auxiliary control oil pump
The auxiliary control oil pump is used to operate the governing actuators and act as a trip circuit to trip the turbine manually or during emergencies. The control oil pump supplies the required pressure needed for the actuators. The control oil pump will auto start and stop with the help of a pressure switch installed in the process line.
Emergency oil pump
The EOP operated by the means of DC supply, in case the AC supply is not available. In case emergency condition the EOP will automatically start when reaches the setpoint and cutoff after reaching adequate pressure set point.
Vapour extractor pump
The lube oil circulated will pick up the temperature and some moisture from the bearing. That gets collected in the lube oil tank has to be removed otherwise it may lead to an explosion by pressure build up. The pump will remove all the vapour from the lube oil tank.
Oil cooler and filter
The temperature of the outcoming oil is cooled with the help of a water exchanger. The water will take away the temperature from the oil and it passes through the oil filter. The filter bag will remove the impurities from the oil. As it may damage the bearings of the turbine and generator. The lube oil cooler is protected by the inlet and outlet temperature element. And the filter choke is identified by the differential pressure switch installed between the filters.
Overhead oil and accumulator
These are installed for extra protection the oil land will be installed above the level of the lube oil tank. By the height, we will get pressure around 1kg/cm2. And the accumulator will manage the pressure to some extend in case of any pump got tripped. Both the system will maintain pressure for a while instead of stripping the turbine due to low oil pressure.
