低容值半桥型模块化多电平变换器直流故障辅助清除策略  

Auxiliary Strategy for DC Fault Clearing of Low Capacitance Half-Bridge Modular Multilevel Converter

作　　者：樊强 俞永杰 夏嘉航 赵成勇 许建中 Fan Qiang;Yu Yongjie;Xia Jiahang;Zhao Chengyong;Xu Jianzhong(State Key Laboratory of Alternate Electrical Power System with Renewable Energy SourcesNorth China Electric Power University,Beijing 102206 China;State Grid Zhejiang Hangzhou Qiantang New District Power Supply Company,Hangzhou 310000 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),北京102206 [2]国网浙江省电力有限公司杭州市钱塘新区供电公司,杭州310000

出　　处：《电工技术学报》2022年第14期3713-3722,共10页Transactions of China Electrotechnical Society

基　　金：中国华能集团有限公司总部科技资助项目(HNKJ20-H88)。

摘　　要：通过谐波电流注入方式可有效减小子模块电容容值,进而降低模块化多电平变换器(MMC)的体积和质量,实现MMC的轻型化。该文通过对低容值半桥MMC直流故障工况特性的理论分析,指出在其他参数不变的情况下,低电容容值下的子模块电容存在放电速度快的现象,可导致故障清除过程中子模块低压闭锁问题。从等电荷角度出发,提出一种基于低容值半桥MMC的直流故障辅助清除策略。通过在MMC故障清除过程中根据电容比调整相投入子模块总数,可有效减小MMC子模块电容的放电量并实现系统的快速恢复。基于PSCAD/EMTDC仿真环境下搭建仿真程序,通过仿真和实验验证了低容值MMC故障辅助清除策略的有效性。The current injection method can reduce the capacitance value of bridge arm sub modules(SMs),thereby reducing the volume and weight of MMC,and realizing the lightweight of MMC.Based on the theoretical analysis of the characteristics of low capacitance MMC in DC fault conditions,it is pointed out that the discharge speed of SM sunder low capacitance is fast when other parameters remain unchanged,which may lead to low voltage blocking of SMs during the DC fault clearing process.From the perspective of equivalent charge,a DC fault clearing strategy based on low capacitance half bridge MMC is proposed.By adjusting the total number of SMs in each phase according to the capacitance reduction ratio in MMC during the fault clearing process,the discharge capacity of the SM capacitors can be effectively reduced and the system recovery can be accelerated.A simulation program is built in PSCAD/EMTDC simulation environment,and the effectiveness of auxiliary strategy for DC fault clearing in low capacitance MMC is verified.

关 键 词：电流注入 低容值半桥 MMC 等电荷 快速恢复 直流故障清除策略 实验验证 

分 类 号：TM721.1[电气工程—电力系统及自动化]