A Novel DC Circuit Breaker with Fast Breaking Capability in Full Current Range

Abstract

With the rapid development of DC power system in recent years, more stringent requirements have been put forward for the rapid reliability of DC circuit breakers. At present, most hybrid circuit breakers widely used create artificial zero crossing by injecting current opposite to short-circuit current. However, when it comes to the small current, the injected current may reverse puncture the contacts of the high-speed mechanical switch. And this results in the difficulty of extinguishing the arc between the contacts of the high-speed mechanical switch during disconnection, prolonging the disconnection time and adversely affecting the system. This paper presents a double break DC circuit breaker structure based on double capacitor structure. In the process of current breaking, the capacitor with small capacitance is used to commutate for small current, and the double capacitor parallel method is used to complete the current transfer for large current. The working principle of the circuit breaker is analysed, and the appropriate parameters are selected through simulation.