High-speed current interruption performance of hybrid DCCB for HVDC transmission system

DC circuit breakers (DCCBs) are an essential component for protecting multi-terminal HVDC transmission systems. DCCBs are required to have rapid fault clearing and high current interruption, as well as low power loss under normal operation. A hybrid DCCB constituted of a semiconductor breaker and a mechanical switch was investigated to achieve rapid fault clearing, within 3 ms, and interruption of a 9 kA current. In the current interruption, the current is commutated from the mechanical switch to the semiconductor breaker, and is then interrupted quickly by the semiconductor breaker. We analyzed and evaluated the operation and the interruption ability of the respective parts, and tested the interruption ability of the hybrid DCCB. The DCCB successfully interrupted a 9 kA fault current within 3 ms.