Effect of impact capacitor on overvoltage in neutral bus of converter station

In order to study the suppression effect of the overvoltage when the Impact capacitor is applied in the neutral bus of the High-voltage Converter station, this paper takes the BIN-JIN HVDC transmission project as the research object and establishes an internal overvoltage calculation model in the PSCAD/EMTDC. The variation of overvoltage amplitude in neutral bus which is in the ground short circuit fault and valve triggering pulse loss fault situation is calculated and analyzed under different impact capacitor configuration schemes. The calculation results showed: installing impact capacitor can significantly reduce the overvoltage level in the neutral Bus of the converter station; and the more the capacity of the impact capacitor increased, the more obvious the suppression effect is; The impact capacitor has a restraining effect on the overvoltage of the neutral bus only when it is on the same side with the bus. To sum up, the impact capacitor could be installed to reduce the level of the inner overvoltage.