Research on Topology and Operating Principle of a Novel Current-limiting Hybrid DC Circuit Breaker
Compared with AC transmission system,DC transmission system has the advantages of low line loss and high efficiency.High voltage DC circuit breaker is one of the key technologies in high voltage DC transmission sys-tem.This paper introduces the topology of a new type of current-limiting hybrid DC circuit breaker,which consists of four parts:mechanical circuit breaker,solid state circuit breaker,buffer absorbing circuit and fault current limiting single circuit.The circuit breaker integrates the advantages of high reliability and low on-state loss of mechanical circuit breaker,and the advantages of fast action of solid state circuit breaker.It has the advantages of low cost,large capacity and small volume.This paper also analyzes the working principle,closing process and opening process of the new type limited current hybrid DC circuit breaker.Finally,the simulation model is built in the simulation soft-ware PSCAD.The simulation results show that the new current-limiting hybrid DC circuit breaker topology can effec-tively limit the rise rate of the fault current and reduce the DC short-circuit fault current when the DC short-circuit fault occurs,so as to realize the zero voltage soft closure and zero current soft opening of the mechanical circuit breaker.The new circuit breaker can reduce cost and volume.
current-limiting hybrid DC circuit breakerfault currentclosingopening