Assessment and modelling of switching technologies for application in HVDC-circuit breakers

Abstract: A key element for future DC-grids is a DC circuit breaker that in case of a short circuit fault reliably can turn off a short circuit current. AC circuit breakers are well known components that has been in use for a long time in AC-grids. The AC circuit breaker is designed to interrupt the current at its natural current zero crossings. In DC grids such does not exists, therefore AC breakers can not be directly applied in DC grids. Different concepts and technologies to solve this problem is available. In this work three different DC-Circuit breaker topologies that show good potential in the medium voltage range has been modeled namely • Resonance Hybrid DC Circuit Breaker • Active Turn-off Hybrid DC Circuit Breaker • Snubbered Hybrid DC Breaker The three different breaker concepts has been analyzed and compared for their ability to limit short circuit current. The comparison shows that the Snubbered DC Circuit breaker has the best short circuit current limiting performance. The maximum short circuit current during the turn-off process is 20 % lower than for the other two DC breaker topologies which shows the aproximately the same sort circuit current limiting performance.