Dc circuit breaker

Abstract

A DC circuit breaker includes: a mechanical switch provided on an electrical path through which a direct current flows; and a semiconductor switch connected in parallel with the mechanical switch. The mechanical switch includes a gas disconnector and a vacuum circuit breaker connected in series. Normally, the direct current flows through the mechanical switch. When interrupting the direct current, the vacuum circuit breaker is made nonconductive to allow the direct current to be commutated to the semiconductor switch, and subsequently the gas disconnector and the semiconductor switch are made nonconductive. A vacuum circuit breaker having a low withstand voltage can be used.

Dependencies are inferred from the claim text.