Experimental Study of Enhanced Active Resonant DC Circuit Breakers

Abstract

Enhanced active resonant (EAR) DC circuit breakers (DCCBs) are a novel type of DCCB that use a discharge closing switch as interruption medium. A technical limitation of discharge closing switches is the minimum voltage across the main gap required for successful triggering. A novel commutation process creating the minimum voltage internally is proposed, which allows to simplify the EAR DCCB configuration and to reduce its component count. In the prototype, the discharge closing switch is implemented with a triggered vacuum gap. Experiments show that the triggered vacuum gap can be triggered reliably down to a voltage of 50 V and that the discharge in the triggered vacuum gap is highly oscillatory at low current. The originally proposed EAR DCCB configuration has to be tuned such that the commutation to the triggered vacuum gap succeeds at low current. Conversely, the novel commutation process decouples the minimum voltage from the current level by adjusting the triggering delay. This allows reliable commutation irrespective of the operating conditions. It is shown that the novel commutation process does not adversely affect DC interruption. Proactive commutation operation and auto-reclosing strategies are demonstrated.

Bidirectional Hybrid DC Circuit Breaker With Zero Voltage and Current Switching for Radar Power System

“…The HCB presents remarkably lower conduction power losses, similar to the mechanical circuit breakers used in ac power systems. Additionally, the fault interruption speed of the HCB is also better compared to the MMCBs [7], [11]- [15]. However, the fault interruption speed of almost all the existing HCBs depends completely on the speed (turn-on delay plus the reaction delay) of the mechanical switch or the disconnector.…”