基于电容换相的混合式直流断路器设计与仿真

Design and Simulation of Hybrid DCCB Based on Capacitor Commutation

直流断路器作为直流输电系统的核心装备,有必要设计一种具备重合闸功能、成本较低、能快速切断故障电流和避雷器吸能较低的直流断路器。该文提出了一种基于电容换相混合式直流断路器(hybrid DC circuit breaker based on capacitor commutation,CC-HDCCB),CC-HDCCB拓扑能有效降低直流断路器的导通损耗;主支路机械开关在零电流零电压下分断,显著降低了机械开关的分断压力;利用电容换相模块的对称性,仅采用2组晶闸管实现双向故障电流分断和重合闸功能,具有分断速度快、可靠性高、对器件要求低、避雷器吸能小的优点。该文对CC-HDCCB的工作原理进行研究分析,并提出通用的CC-HDCCB参数设计流程,最后利用PSCAD/EMTD软件进行仿真验证。仿真结果表明:CC-HDCCB拓扑各器件电压电流相对较低,与相关断路器对比,CC-HDCCB拓扑的分断压力和避雷器吸能压力小,验证了该文所提结构的合理性和经济性。

DC circuit breaker(DCCB)is the core equipment of DC transmission system,and it is necessary to design a DCCB with reclosing function and relatively low cost which can quickly cut off the fault current and reduce the energy absorption of arrester.In this paper,a hybrid DC circuit breaker based on capacitor commutation(CC-HDCCB)topology is proposed,and the CC-HDCCB topology can effectively reduce the conduction loss of DC circuit breaker.The main branch mechanical switch breaks under zero current and zero voltage,which significantly reduces the breaking pressure of the mechanical switch.By using the symmetry of capacitor commutation module,only two groups of thyristors are used to realize bidirectional fault current breaking and reclosing function,which has the advantages of fast breaking speed,high reliability,low requirement for devices and small energy absorption of arrester.In this paper,the working principle of CC-HDCCB is studied and analyzed,and a general CC-HDCCB parameter design process is proposed.Finally,simulation verification is carried out by the PSCAD/EMTD.The simulation results show that the voltage and current of each device in CC-HDCCB topology is relatively low.Compared with related circuit breakers,the CC-HDCCB topology has lower breaking pressure and arrester energy absorption pressure,which verifies the rationality and economy of the proposed structure.