The oil pressure of the main steam valve of the turbine is low; it is not possible to start the machine
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Qingdao Turbine: The oil pressure of the main steam valve is low (0.1 MPa), with the normal value being 0.5 MPa; therefore, it is not possible to start the machine. I would like to ask everyone for advice on what aspects to consider in order to find the cause! Thank you!
Could you explain it in detail? Thank you!
It might be that the combination valve is blocked; clean it. How long has your equipment been in use?
It is possible that the air bag of the high-pressure accumulator is leaking, resulting in insufficient air pressure. This is because every time, after the gate is engaged for a start-up operation and all the control valves are opened, the system oil pressure begins to drop. After the gate is engaged for start-up, the high- and medium-pressure main steam valves are fully open, and the control valves also start to operate; at this point, the amount of oil in the system is insufficient, so a high-energy accumulator is used to replenish the system pressure. If the high-energy accumulator leaks or the accumulator bypass valve becomes loose, oil will flow from the bypass valve to the return pipe, which can also cause a drop in system oil pressure during startup. Therefore, when using specialized tools to measure the nitrogen pressure in each accumulator, it was around 9.8 MPa, indicating that the measurement results were normal. The bypass valves for all accumulators were tightened again; the unit was started up once more, and its speed rose to 99 r/min. The unit tripped again due to low system oil pressure.
It is recommended to consult the DEH manufacturer, Koyo?