串入耦合变压器高压直流断路器拓扑分析

Topological Analysis of HVDC Circuit Breaker With Coupling Transformer

常规能源的稀缺,加快了以清洁能源为主导的全球互联坚强智能电网的构建。大规模清洁能源接入电网,推动了直流电网技术的进步。而高压直流断路器作为直流电网的核心设备之一,近年来渐渐成为研究热点。相比较交流电流,直流电流无自然过零点,分断难度大,在高压大容量系统中尤为明显。在简要回顾直流断路器研究现状之后,提出一种带耦合变压器的无弧分断高压直流断路器拓扑。给出拓扑结构,分析其工作原理。建立各阶段等效模型,并在此基础上对关键组件参数进行设计。以舟山5端柔性直流输电工程为依据,开展断路器仿真研究,验证理论分析的正确性,仿真结果表明:该拓扑直流断路器能有效开断直流电流,为直流断路器的设计提供了依据。

The scarcity of conventional energy resources accelerates the construction of strong smart grid with global energy interconnection. The rapid progress of large-scale clean energy accessing to the power grid promotes the development of DC grid technologies. High voltage direct current(HVDC) circuit breaker as one of the key equipments of the DC grid has gradually attracted more and more attentions. Direct current is more difficult to be interrupted comparing to alternating current because of without natural zero-crossing point, especially in the high voltage and large capacity system. The research status of DC circuit breaker is briefly reviewed firstly. Then a novel topology of HVDC circuit breaker with coupling transformer is proposed. Its topology is presented and its operating principle is analyzed. The equivalent model for different stages is established, based on which the key component parameters are designed. Operating characteristic of the HVDC circuit breaker is simulated relying on Zhoushan 5-terminal flexible HVDC project. Simulation results have verified the correctness of the theoretical analysis and the effectiveness of the novel HVDC circuit breaker in interrupting the fault current in the flexible HVDC transmission grid. This provides a basis for HVDC circuit breaker design.