Design of a Double Break Current Injection DC Circuit Breaker

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, series and parallel breakers are commonly used in medium-voltage DC circuit breakers to improve the breaking capacity, but there are some problems such as poor uniformity of breakers, large size of circuit breakers and high cost. In this paper, a double-break DC circuit breaker structure based on reactance coupler is proposed. In the process of current breaking, two vacuum switches in series operate simultaneously, and the capacitive discharge and reactance coupler are used to realize rapid current commutation, which improves the voltage bearing capacity of the circuit breaker. Connecting IGCT in the commutator branch can shorten the break time and make reclosing easier. The working principle of the circuit breaker is analyzed, and the rationality of the proposed scheme is verified by simulation calculation.