具备闭锁和非闭锁模式抑制直流故障电流的新型模块化多电平变换器拓扑  

A New Modular Multilevel Converter Topology with Capability of DC Faults Clearing under Blocking and Non-Blocking Mode

作　　者：束洪春[1] 邵宗学 江耀曦[2] 包广皎 王文韬 Shu Hongchun;Shao Zongxue;Jiang Yaoxi;Bao Guangjiao;Wang Wentao(Faculty of Electric Power Engineering Kunming University of Science and Technology,Kunming 650051 China;Faculty of Information Engineering and Automation Kunming University of Science and Technology,Kunming 650051 China)

机构地区：[1]昆明理工大学电力工程学院,昆明650051 [2]昆明理工大学信息工程与自动化学院,昆明650051

出　　处：《电工技术学报》2022年第21期5526-5540,共15页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金重点项目(52037003);云南省重大科技专项计划(202002AF080001)资助。

摘　　要：现有直流线路短路故障电流抑制方法存在抑制速率与经济性的矛盾。该文提出了可在闭锁和非闭锁两种模式下低成本实现直流故障电流快速抑制的模块化多电平变换器(MMC)子模块拓扑,即五电平钳位交叉子模块(FLCCSM)结构;分析了闭锁和非闭锁抑制模式下的直流故障穿越过程;解析了在两种抑制模式下满足故障穿越条件的子模块电容投入到故障回路的配置数量;提出了电容成组投切的均衡控制策略以提升其均压效果。Matlab/Simulink仿真结果表明,FLCCSM-MMC在闭锁模式下能将直流故障电流快速抑制到零,主要用于处置直流永久性故障。在非闭锁模式下能将桥臂电流快速抑制到小于2倍桥臂电流额定值,非闭锁模式下MMC仍具有输送一定功率的能力,适用于处置直流瞬时性故障,且故障前后电容电压保持均衡。FLCCSM-MMC具有故障电流抑制速度快、可靠性高、器件成本低、运行损耗小的优势。The existing DC short-circuit fault current clearing methods have the contradiction between clearing rate and economy.A five-level clamp crossed sub-module(FLCCSM)modular multilevel converter(MMC)topology is proposed,which can achieve rapid clearing of DC fault current at low cost in both blocking and non-blocking modes.The DC fault ride-through processes in the blocking and non-blocking clearing modes are analyzed;the configuration numbers of the capacitors of the sub-modules in the fault current path that meets the fault ride-through conditions in the two clearing modes are deduced;the balanced control of the capacitor inserting in group strategies to improve its voltage equalization effect is proposed.Matlab/Simulink simulation results show that FLCCSM-MMC can quickly clear the DC fault current to zero in the blocking mode,it is mainly used to deal with DC permanent faults.In the non-blocking mode,FLCCSM-MMC can quickly limit the arm current to less than 2 times of the rated value of the bridge arm current,and MMC still has the ability to transmit a certain amount of power,which is more suitable for dealing with DC transient faults,furthermore the capacitors voltages remain balanced before and after the fault.FLCCSM-MMC has the advantages of fast fault current clearing,high reliability,low device cost,and low operating loss.

关 键 词：模块化多电平变换器(MMC) 五电平钳位交叉子模块 直流故障电流抑制 闭锁和非闭锁模式 电容电压均衡控制 

分 类 号：TM46[电气工程—电器]