一种H桥型高压直流断路器的拓扑结构和故障隔离策略研究

Study on Topology Structure and Fault Isolation Strategy of H-bridge Type HVDC Breaker

为降低混合式高压直流断路器的昂贵造价,提出了一种H桥型高压直流断路器,并对其联接于直流正负极时不同的故障隔离控制策略分别进行了研究。H桥型高压直流断路器沿用了混合式高压直流断路器的关键部件和断流理念,利用H桥结构特有的电流流向特性,对混合式直流断路器内的关键部件进行了整合,通过重新布局使得直流断路器内的IGBT个数大幅减少。在保证同等直流故障处理能力的前提下,相比于混合式高压直流断路器,H桥型高压直流断路器的投资成本大幅降低。为验证H桥型高压直流断路器及其故障隔离策略的有效性,在PSCAD/EMTDC内建立了一个三端单极直流网络模型。仿真结果验证了H桥型高压直流断路器在隔离直流线路故障方面的可行性和有效性。

In order to reduce the great cost of the hybrid HVDC breaker, a H-bridge type HVDC breaker is proposed in this paper, and different fault isolation strategies are studied in the case of the positive and negative poles connection. The key components and fault isolation principle of the hybrid breaker are used in the H-bridge type breaker. According to the characteristic of current flow direction of the H-bridge structure, the key components of hybrid HVDC breaker are integrated, and the number of IGBT in the HVDC breaker is greatly reduced by re-layout. The fault clearing capability of the H-bridge type HVDC breaker is equal to the hybrid breaker, but its investment cost is reduced dramatically. A model of a three-terminal monopolar HVDC network is developed in PSCAD/EMTDC to verify the validity of the proposed breaker and its fault isolation strategies. Simulation results prove validity and feasibility of the proposed solution.