During normal operation period of a 600 MW steam turbine unit in one power plant

the shutdown of said unit has been triggered by the actuation of its low oil pressure protection due to abrupt drop of the lubricating oil pressure.Through analysis of related parameters in manipulation of operation and in thermodynamic measurement of lubricating oil transporting equipment and system before and after the shutdown

finally

it is determined that the cause leading to abrupt drop of the lubricating oil pressure is due to the actual oil-level in oil tank was too low

resulting in air accumulation in the pipeline of oil system.For this

some corresponding measures

such as adopting calibrated oil-level meter

enhancing the oil-level

lengthening the retention time of oil in the oil tank

and opening vent holes etc.

have been put forward.After implementation

the oil pressure has restored to be normal.