新型限流式混合直流断路器拓扑与工作原理研究

Research on Topology and Operating Principle of a Novel Current-limiting Hybrid DC Circuit Breaker

相比于交流输电系统,直流输电系统有线损低、效率高的优点。高压直流输电系统中高压直流断路器是关键技术之一。介绍了新型限流式混合直流断路器拓扑,该新型断路器共包括4个部分:机械断路器、固态断路器、缓冲吸收电路以及故障电流限制单路。该断路器集合了机械式断路器可靠性高、通态损耗低等优点,与固态断路器动作迅速的优点,具有成本低、容量大、体积小等优点。还分析新型限流式混合直流断路器的工作原理,合闸过程以及分闸过程。最后在仿真软件PSCAD中搭建了仿真模型。仿真结果表明:新型限流式混合直流断路器拓扑可以在发生直流短路故障时,有效限制故障电流的上升率,降低直流短路故障电流,实现机械断路器零电压软闭合,零电流软断开。该新型断路器可实现降低成本、体积。

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 system.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 software PSCAD.The simulation results show that the new current-limiting hybrid DC circuit breaker topology can effectively 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.