一种基于反并联晶闸管全桥子模块的新型电容换相换流器

An Enhanced Capacitor Commutated Converters Based on an Anti-parallel Thyristor Full Bridge Submodule

为了改善电容换相换流器(capacitor commutated converter,CCC)的故障特性,提出了一种基于反并联晶闸管全桥子模块的新型电容换相换流器拓扑(enhanced capacitor commutated converter,ECCC)。ECCC从提高电容电压可控性的角度出发,将换流阀和换流变压器之间的固定电容替换为反并联晶闸管全桥子模块。设计了子模块晶闸管与阀臂晶闸管的协调控制策略;分析了子模块晶闸管的电压电流应力。在PSCAD/EMTDC环境中对ECCC的子模块电压电流应力、抵御换相失败的能力和换相失败后恢复能力进行了仿真研究。结果表明:ECCC可以有效降低换相失败发生的概率;同时,由于其对电容电压的灵活控制能力,可以有效避免换相失败发生后类似CCC换流器失去自恢复能力的问题,具备故障快速恢复能力;并且,子模块的电压电流应力均在合理范围内。

With the anti-parallel thyristor full bridge submodule（APT-FBSM） embedded between the converter and the converter transformer, an enhanced capacitor commutated converter（ECCC） was proposed in this paper to improve the transient performance of capacitor commutated converters（CCC） under fault conditions. The coordinated control strategy between APT-FBSM and thyristor valves was presented. The voltage-current stress of the T-FBSM was also evaluated. Then the voltage-current stress, the ability to mitigate the commutation failure（CF） and the fault recovery capability after CF were investigated in PSCAD/EMTDC. The results show that the ECCC can reduce the CF risk effectively, and can improve the fault recovery performance by its flexible control of capacitor voltages. Meanwhile, the voltage-current stress of APT-FBSM can be controlled within the reasonable range.