新型具有限流功能多端口高压直流断路器拓扑

直流断路器(DC circuit breaker,DCCB)是提高直流电网安全稳定运行的关键设备。针对现有的DCCB投入的数量多导致成本过高、短路故障时电流过大、避雷器吸收能量过多等问题,提出了一种新型具有限流功能的多端口高压直流断路器拓扑(multi-port DC circuit breaker,MP-DCCB)。通过改进DCCB拓扑结构研究其性能,对新型拓扑的工作原理、故障分断过程进行理论分析,并给出相关参数及选取依据,最后用PSCAD软件搭建相应的仿真模型,并进行验证。与常规DCCB方案相比,故障电流减少了48.6%;避雷器上吸收能量、关断电流和关断时间分别减少了54.8%、52.4%和0.8 ms。该新型MP-DCCB具有良好的可靠性与经济性,仿真结果验证了所提新型具有限流功能的多端口高压直流断路器拓扑可适用于当前直流电网。

New Topology of Multi-port High-Voltage DC Circuit Breaker with Current-Limiting Function

DC circuit breaker (DCCB) is the key equipment to ensure the safe and stable operation of DC power grid. For the existing DCCB, the cost is too high due to the large number of devices in operation, large current during short-circuit faults, and too much energy absorbed by the arrester. A power electronic multi-port HVDC circuit breaker (MP-DCCB) with current limiting is proposed. The performance of DCCB is studied by improving its topology. The working principle and fault breaking process of the new topology are analyzed theoretically. The relevant parameters and selection basis of the device are given. Finally, the corresponding simulation model is built and verified with PSCAD software. Compared with the conventional DCCB scheme, the fault current is reduced by 48.6%; the absorbed energy, turn-off current and turn-off time of the arrester are reduced by 54.8%, 52.4% and 0.8 ms, respectively. Therefore, the new MP-DCCB has good reliability and economy, and the simulation results verify that the new topology scheme of power electronic multi-port HVDC circuit breaker with current limiting can be applied to the DC power grid.