Hybrid Circuit Breaker Using Fast Mechanical and Semiconductor Switches

A new circuit and corresponding operating principle for direct current hybrid circuit breaker (DC HCB). The new circuit exclusively applies a capacitor directly in the path of main semiconductor switch, making the circuit more simplified with less components. This DC HCB can be used to clear faults in bidirectional DC or AC power systems and enables the mechanical switch to operate during no-load conditions.  A branch consisting of capacitor in series with semiconductor switch(es) is connected in parallel with a branch consisting of a mechanical switch. The principle consists of four stages: Standby, Commuting, Regulating and Tailing.