考虑快速重合闸的快速泄流型混合式直流断路器

Rapidly Energy Dissipating Hybrid DC Circuit Breaker Considering Fast Reclosing

直流断路器是柔性直流输电的关键保护设备,现有的高压直流断路器主要有2条技术路线:基于人工过零的机械式方案与基于电力电子器件的混合式方案。以一种"快速泄流型混合式直流断路器"拓扑方案为基础,首先介绍了该方案的拓扑结构与分断过程,探究了直流断路器对重合闸时间的要求,并对该方案进行了重合闸时间的适应性分析,指出其不适应于快速重合闸的缺点。然后在原方案的不同位置加入阻容元件,形成了3种改进方案,并通过理论分析和仿真分析手段对其进行验证和对比。结果表明:3种改进方案均可大幅加快故障侧电感的放电速度,从而满足快速重合闸的要求;方案2、方案3适用于对故障限流要求比较严格而对成本不敏感的场合,方案1简单易行,可在大幅加快故障侧电感放电的同时仅小幅减缓非故障侧放电,是综合效果最好的方案。

DC circuit breaker(DCCB)is a key protective device in voltage-source-converter-based high-voltage DC transmission(VSC-HVDC).The existing high-voltage DCCBs are mainly divided into two technical routes:the mechanical type based on artificial-current-zero method and the hybrid type based on power electronics devices.Based on a DCCB topology scheme named‘rapidly energy dissipating hybrid DCCB’,this paper introduces its topological structure and interruption process firstly.After the exploration of requirements for the reclosing time of DCCB,adaptability analysis of the reclosing time is carried out for the scheme,and its drawbacks of inadaptation to fast reclosing are pointed out.Then,three improved topology schemes are formed by adding RC components at different locations in the original scheme,and they are verified and compared by the method of theoretical analysis and simulation analysis.The results show that all of the three improved topologies can largely accelerate the discharging speed of fault side inductor,and therefore can meet the requirements of fast reclosing.Scheme 2 and Scheme 3 are suitable for the occasion of strict demands for current limiting but low demands for cost.Scheme 1 has the best comprehensive effect because it is not only simple and easy but also can greatly accelerate the discharging speed of fault side inductor while only slightly slows down that of the non-fault side.