摘要
模块化多电平换流器(modular multilevel converter,MMC)在柔性直流输电领域应用广泛,但传统的半桥型子模块(half-bridge sub-module,HBSM)不具备直流侧故障自清除的能力。为此,提出一种具备直流侧故障自清除能力的改进电容型子模块拓扑结构,分析了新型子模块的基本结构及工作原理;根据子模块闭锁后的系统等效电路,阐述了新型子模块的故障阻断机理;为兼具故障自清除与低损耗的特点,给出了新型子模块与HBSM混合的MMC桥臂设计方案;并从器件耐压水平及经济性两个方面,与常见的子模块做详细比较分析;最后在PSCAD/EMTDC中搭建了双端MMC系统对提出的子模块特性进行了仿真验证。仿真结果表明,直流侧故障后的故障电流在子模块闭锁后能迅速清零,验证了所提子模块直流侧故障自清除的有效性。
Modular multilevel converter(MMC)is widely used in the field of flexible DC transmission,but the traditional half bridge sub-module(HBSM)does not have the ability of DC side fault self-clearing.In this paper,an improved capacitive sub-module topology with DC side fault self-clearing capability is proposed,and the basic structure and working principle of the new sub-module are analyzed.According to the system equivalent circuit after the sub-module is locked,the fault blocking mechanism of the new sub-module is described.In order to possess the characteristics of fault self-clearing and low loss,the design scheme of MMC bridge arm with the new sub-module and HBSM is given.From the two aspects of device voltage withstand and economy,a detailed comparison and analysis are carried out with the common sub-modules.Finally,a two-terminal MMC system is built in PSCAD/EMTDC to simulate and verify the characteristics of the proposed sub-module.The simulation results show that the fault current after DC side fault can be quickly cleared after the sub-module is locked,which verifies the effectiveness of the proposed sub-module DC side fault self-clearing.
作者
罗雍溢
王渝红
宋瑞华
毕经天
叶葳
闵杨晰
LUO Yongyi;WANG Yuhong;SONG Ruihua;BI Jingtian;YE Wei;MIN Yangxi(College of Electrical Engineering,Sichuan University,Chengdu 610065,China;China Electric Power Research Institute,Beijing 100192,China)
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2021年第12期4510-4517,共8页
High Voltage Engineering
基金
国家电网公司基础前瞻科技项目(含多电力电子装备电力系统宽频振荡稳定分析及量化评估研究)(SGTYHT/18-JS-206)。
