基于强迫过零技术的自换向高压直流断路器

为了提高混合式直流断路器开断能力、降低直流短路故障对系统的危害，提出了一种基于强迫过零技术的自换向高压直流断路器。该断路器利用晶闸管与二极管代替了关断支路的IGBT元件，并通过单个预充电电容和强制过零技术实现了切除断路器两侧故障，减少系统的安装成本。详细描述所提直流断路器的拓扑结构、工作原理，并通过动作时序和等效电路分析元件的参数取值方法，最后应用PSCAD仿真软件搭建三端环网模型对其进行仿真验证。结果表明，该方案可以实现故障线路的可靠切除，断路器经过一次预充电后无须再次充电即可恢复切除能力，具有较好的经济性。

A Self-commutated HVDC Circuit Breaker Based on Forced Zero Crossing Technology

In order to improve the breaking capacity of Hybrid DC circuit breaker and reduce the harm of DC short circuit fault to the system, we proposed a self-commutated HVDC circuit breaker based on forced zero crossing technology. The circuit breaker replaces the IGBT components with thyristors and diodes, and realizes the cut-off of the faults on both sides of the circuit breaker through a single precharge capacitor and forced zero crossing technology, which reduces the installation cost of the circuit breaker. In this paper, the topological structure and working principle of the DC circuit breaker are described in detail, and the parameter selection method of the components is analyzed through the action sequence and the equivalent circuit. Finally, the three-terminal ring network model is built by PSCAD simulation software and verified by simulation. The results show that the scheme can realize the reliable cut-off of the fault line, and the circuit breaker can recover the cut-off ability without recharging after one precharge, thus having good economy.