全桥型MMC-HVDC直流故障自清除控制保护策略研究

Full bridge-type MMC-HVDC with DC fault clearing protection strategies

当前已投入运行的柔性直流输电工程中换流器不具备直流侧故障自清除能力,制约了架空线应用于柔性直流输电线路发展。研究全桥型模块化多电平换流器拓扑结构,其桥臂是由全桥子模块(FBSM)组成,分析全桥型MMC工作原理,并研究全桥MMC实现直流侧故障自清除的机理。最后,通过PSCAD/EMTDC软件仿真验证该全桥型换流器能够有效阻断直流侧故障电流,进一步对比传统MMC验证了全桥型换流器清除直流侧故障的可行性和有效性,具有较好的应用前景。

Considering the disadvantages that converter utilized for the high voltage direct current(HVDC)transmission projects cleans the DC side fault in current operations,it seriously restricts the application of overhead line to HVDC transmission projects.This paper focuses on the full bridge module of multilevel converter topology structure with bridge arm composed of full bridge modules(FBSM).Then the working principle of full bridge MMC and full bridge MMC mechanism is analyzed to achieve cleaning fault in the DC side.Finally,the full bridge switch converter is simulated via the software PSCAD/EMTDC.It is shown that the fault current on the DC side is effectively blocked.In addition,a further comparison is made between the full bridge MMC and traditional MMC to verify the feasibility and effectively.The full bridge MMC has a good application prospect.