HVDC hybrid circuit breaker based on SF6 interrupter and vacuum interrupter in series

The hybrid circuit breaker (HCB) which consists of SF6 interrupter (GI) and vacuum interrupter (VI) connected in series has been put forward to be applied in HVDC system. The paper analyses the theoretical basis of HCB and designed the implement plan. Vacuum has the rapid dielectric strength recovery speed which has the advantage of interrupting high frequency current while SF6 has the dielectric strength. The current zero was easily achieved by driven-oscillation because of the superior negative resistance characteristic of SF6. After current post zero, VI endures initial transient recovery voltage and GI undertakes most of the recovery voltage which is achieved by the nonlinear resistor and the dividing capacitor connected in parallel with the VI and GI respectively. The optimum matching parameters was gained through the simulation of HCB. The simulation results of static voltage distribution and transient recovery voltage distribution verified the analytical model. The result provided the basis for further studying of HCB interruption.