一种具备直流故障清除能力的新型MMC子模块拓扑

当基于模块化多电平换流器(MMC)的高压直流输电(MMC-HVDC)系统直流线路发生短路故障时,传统半桥子模块存在无法通过闭锁阻断直流故障电流的问题.对此,提出一种具备直流故障清除能力的基于半桥的五电平新型子模块(FLHBSM)拓扑.FLHBSM与传统半桥子模块具有相同的控制结构,并具备了直流故障清除能力.相比其他具备...

Novel MMC sub-module topology with DC fault clearing capability

When short circuit fault occurs on DC line of MMC-HVDC(High Voltage Direct Circuit based on Modular Multilevel Converter) system, the DC fault current cannot be blocked by traditional HBSM(Half-Bridge Sub-Module). In this regard, a FLHBSM(novel Five-Level Half-Bridge Sub-Module) topology is proposed. FLHBSM has the same control structure as HBSM with the addition of DC fault clearing capability. Compared with other sub-module topologies with DC fault clearing capability, FLHBSM reduces the number of switching devices and the area occupied by the converter station, reduces the loss and provides high control flexibility, and not only improves the economy of MMC, but also enhances its operation reliability. Meanwhile, FLHBSM can be compatible with the capacitor voltage balancing strategies suitable for HBSM, and can choose better capacitor voltage balancing strategy according to the actual needs. A simulation model of bi-terminal ±100 kV 21-level MMC-HVDC system based on FLHBSM is built on MATLAB/Simulink platform, which verifies the effectiveness of DC fault clearing capacity by using FLHBSM.