Abstract: The lubricating oil system of the turbine generator unit relies on the DC oil pump significantly in case of turbine unit accidents, if it is not equipped with an independent main oil pump and its electrical connection is weak Once an abnormal event occurs, the DC oil pump cannot be started in time, which will directly lead to the severe accidents of steam turbine shaft break and bearing pad overheated damage. Based on the comparative analysis of the pump starting up test, the upgrade on the electrical and interlock circuit of the lubricating oil system is carried out. Thus the potential risks in the DC oil pump starting process are solved, and the risks of shaft break and bearing pad overheating are lowered. The study results are helpful for the steam turbines of the same type.

Key words: lubricating oil system, optimization, spindle drive oil pump, electric main oil pump, DC oil pump, interlock