Abstract:

By analyzing the tripping of a thermal power unit, it theoretically negates the inevitability of tripping led by shorttime high/low voltage bypass fault opening. Combined with the further analysis on site, it is confirmed that the failure of the deaerator admission check valve was the direct cause of the unit tripping. After the valve fails, it can be opened by the frontandback pressure difference, but it cannot play the role of backstop. Once the unit is greatly reduced in load, it will bring water shock to the water pump turbine,which causes the unit tripping.

Key words:

deaerator, check valve, fourstage extraction, small steam turbine, water shock, trip