适用于直流电网的故障电流主动转移型MMC  

Fault Current Actively Transferring Modular Multilevel Converter in DC Grid

作　　者：蒋纯冰 俞永杰 王鑫 赵成勇 JIANG Chunbing;YU Yongjie;WANG Xin;ZHAO Chengyong(State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources(North China Electric Power University),Changping District,Beijing 102206,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京市昌平区102206

出　　处：《电网技术》2021年第1期170-178,共9页Power System Technology

基　　金：国家自然科学基金项目(51777072)。

摘　　要：柔性直流电网对价格高昂的高压大容量直流断路器(DC circuit breaker,DCCB)的需求限制了其发展与应用。论文提出了适用于直流电网的故障电流主动转移型低成本直流故障隔离方案,对半桥型模块化多电平换流器进行局部改造,使其在具备主动转移故障电流辅助分断故障线路的同时,降低了换流器桥臂子模块内器件的过流程度与过流时间,提高子模块内器件的可靠性。随后阐述了故障电流主动转移方案的工作原理,并对各阶段的故障电流与新增模块内IGBT的电压应力进行理论分析。最后,利用PSCAD/EMTDC进行仿真验证,并将论文方案与混合式DCCB方案的器件使用量进行对比,可知论文方案在换流器出线数目较多的场合具备一定的经济优势。The demand for high voltage and high capacity DC circuit breaker with high cost limits the development and application of flexible DC grid. This paper proposes a fault current transferring MMC and a low-cost DC fault clearance scheme. In this scheme, the traditional half-bridge MMC is partially innovated to actively transfer the fault current to assist isolate the fault line. Besides, it improves the reliability of the devices by reducing the level and time of the over-current. Then, the principle of fault current actively transferring scheme is illustrated and the current in each stage and the voltage stress of the IGBT in the added modules are analyzed. Finally, a simulation model of the proposed scheme is built in PSCAD/EMTDC. By comparing the device usage of the proposed scheme with the hybrid DCCB scheme, it can be seen that the proposed scheme is more economical when the converter has several outlines.

关 键 词：模块化多电平换流器 直流断路器 直流故障电流 

分 类 号：TM721[电气工程—电力系统及自动化]