具有直流故障阻断能力的电流主动转移型MMC  

Active Current-transferring Modular Multilevel Converter with DC Fault Blocking Capability

作　　者：陈铮 陈武[1] 刘忠[2] 左向红 施慎行[4] 薛钟兵[2] CHEN Zheng;CHEN Wu;LIU Zhong;ZUO Xianghong;SHI Shenxing;XUE Zhongbing(Center for Advanced Power-conversion Technology and Equipment,Southeast University,Nanjing 210096,China;State Grid Yangzhou Power Supply Company,Yangzhou 225000,China;State Grid Beijing Electric Power Co.,Ltd.,Beijing 100055,China;Department of Electrical Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]东南大学先进电能变换技术与装备研究所,江苏省南京市210096 [2]国网扬州供电公司,江苏省扬州市225000 [3]国网北京市电力公司,北京市100055 [4]清华大学电机工程与应用电子技术系,北京市100084

出　　处：《电力系统自动化》2021年第4期106-114,共9页Automation of Electric Power Systems

基　　金：国家电网公司科技项目(SGJSYZ00FCJS1900339)。

摘　　要：具有直流故障阻断能力的模块化多电平换流器(MMC)是柔性直流输配电技术的重要支撑设备。针对传统半桥型MMC无法阻断直流短路故障的问题,通过结合现有的故障阻断方案,提出了具有直流故障阻断能力的电流主动转移型MMC。该拓扑增加了断流支路、桥臂阻断支路以及能量吸收支路。直流故障发生后,通过断开断流支路,一方面主动转移故障电流,另一方面实现桥臂电流的换向,进而利用半桥子模块吸收MMC内部故障能量。同时,能量吸收支路中的全桥子模块在闭锁过程中也投入电容以吸收线路侧的故障能量,从而实现了短路故障的快速阻断。文中通过建立电流主动转移型MMC拓扑,详尽分析了故障阻断机理,并在MATLAB/Simulink中搭建了单端100 kV/25电平仿真模型,验证了该拓扑的可行性与有效性。Modular multilevel converter(MMC)with DC fault blocking capability is the key equipment for the flexible DC transmission and distribution technology.Aiming at the problem that traditional half-bridge MMC cannot block DC short-circuit fault,an active current transferring MMC with DC fault blocking capability is proposed by combining the existing fault blocking schemes.The current breaking branch,the bridge arm blocking branch and the energy absorbing branch are added to the topology.Once a DC fault occurs,the current breaking branch is disconnected to transfer the fault current actively and reverse the arm current simultaneously,and then the fault energy in MMC can be absorbed with half-bridge submodules.Meanwhile,capacitors also operate to absorb the fault energy on the line side during the blocking process of full-bridge submodules in the energy absorbing branch.Thus the short-circuit fault is blocked quickly.The fault blocking mechanism is analyzed in detail by establishing the active current transferring MMC model,and a single-end 100 kV/25-level simulation model is built in MATLAB/Simulink to verify the feasibility and effectiveness of the proposed topology.

关 键 词：柔性直流输电 柔性直流配电 模块化多电平换流器 直流故障阻断 直流短路故障 电流换向 

分 类 号：TM46[电气工程—电器] TM721.1