Analysis of Interruption Performance of DC Vacuum Circuit Breaker Under Field and Circuitry Coupling in Electromechanical System

The main factors affecting the fault interruption capability of an active DC vacuum circuit breaker are the structural parameters of the contact surface of the vacuum interrupter, the gap distance at current zero point and the parameters of the commutation circuitry. This paper takes 10 kV/5 kA DC vacuum circuit breaker as the research object, establishes the sheath development model under the coupling of multiple fields and circuitry, and parameterizes the post-arc dielectric recovery strength under the influence of electromechanical parameters. Moreover, the criterion for post-arc re-breakdown is proposed and the limit of breaking current threshold is obtained under the influence of multiple factors.