Simulation and analysis on the interruption process of HVDC vacuum switch with forced current zero

With the fast development of multi-terminal high-voltage direct-current (HVDC) transmission system, a fast HVDC interruption technique is urgently demanded to break the short circuit current in the multi-terminal HVDC transmission system with a rapid rising rate. In this paper, an interruption scheme for HVDC based on vacuum switch and artificial current zero technique is proposed. The modularized main circuit breaker is composed of multiple modules in series, each module consists of a vacuum circuit breaker with fast operation mechanism, a RC snubber branch, and a metal oxide arrester. A triggered sphere gap is adopted for the commutation switch to achieve the bi-directional interruption. A backup circuit breaker is used to interrupt the residual current flowing in the circuit caused by the weak arc extinguishing capacity of the sphere gap. The interruption scheme is modeled and simulated. The current commutation process is analyzed.