Voltage-Sharing Components Configuration of Double-Break Fast Mechanical Switch for a 200 kV Hybrid DC Circuit Breaker

With the construction of 200 kV flexible DC power grid, 200 kV DC circuit breakers have been demanded. The fast mechanical switch, which is an important component in the hybrid DC circuit breaker, usually adopts multi-break structure to meet the requirements of breaking time and effective opening stroke. For a 200 kV double-break fast mechanical switch, the voltage characteristics in the breaking process were analyzed firstly. Then, the distributed capacitances' parameters were calculated by the finite element method. Finally, the voltage-sharing components' parameters were simulated by using PSCAD/EMTDC. It is suggested that the voltage-sharing capacitors' value be selected from 260 pF to 300 pF, 200 Ω for the current limiting resistor, and 200 MΩ for the voltage-sharing resistor. The research can provide a reference for the voltage-sharing design of mechanical switches in non-arc hybrid DC circuit breakers.