Capacitor banks is one of the important reactive power compensation installaton in power system.Usually vacuum circuit breaker is used for switching such installation.It will produce the overvoltage when the restrike occurs in the vacuum circuit breaker opening capacitor banks.The overvoltage may damage vacuum circuit breakers

capacitors or other electrical equipment.With actual operation

the vacuum circuit breaker is usually used in the cable system for reactive power compensation circuit.So the existence of the parasitic capacitance in the system will inevitably involved in the process of the vacuum circuit breaker switching capacitor banks.In this paper

combined with typical compensation circuit in thesubstation

the distribution of the parasitic capacitance is analyzed for the impact of the vacuum circuit breaker opening capacitor banks when the overvoltage appears.Through the equivalent experiment carried out in the laboratory

it is proved that the parasitic capacitance branch current for the power side and load side has been existed.The branch current is of high frequency and high amplitude.In this case

the overvoltage waveforms and data have been obtained when the restrike occurs in the vacuum circuit breaker opening capacitor banks.The results show that

due to the existence of the parasitic capacitance for compensation circuit

which has influence on the overvoltage of vacuum circuit breaker switching capacitor banks.So

the parasitic capacitance should be considered in the overvoltage analysis of vacuum circuit breaker switching capacitor banks.