Study on Closing No-Load Line Switching Overvoltage of Outgoing Lines of 500kV Pumped Storage Power Station

The input capacity of generator and the number of outgoing line circuits of 500 kV pumped storage power station affect the magnitude of switching overvoltage of closing no-load line, thus affecting whether the circuit breaker needs to install closing resistance. By using ATP-EMTP program, this paper studies the switching overvoltage level of 500 kV pumped storage power station under different input capacity of generator and different number of outgoing lines. The results show that the sending system of pumped storage power station is weak network condition, and the switching overvoltage level of the no-load line exceeds the 2.0 p.u. of the China national standard under the operation mode of less input capacity of generator and outgoing lines. By considering the flashover rate calculation of multiple factors, the flashover rate of the closing operation of the line is lower than the 0.04 times / year specified in the China national standard, and the line circuit breaker can not install the closing resistance. The research conclusions show that the terminal voltage of the generator can be adjusted to maintain the bus voltage of 500 kV before closing, or the no-load line operation can be carried out by the large system on the opposite side, and the high or low voltage side of the transformer of the pumped storage power station can be connected to the grid.