混合三端直流输电系统线路故障特性及故障电流抑制策略  

DC Fault Characteristics and Fault Current Suppression Strategy of Three-terminal Hybrid HVDC System Based on LCC and Hybrid MMC

作　　者：韩伟 杨睿璋 刘超 李程昊 孟沛彧 孙仕达 刘磊 向往 文劲宇 HAN Wei;YANG Ruizhang;LIU Chao;LI Chenghao;MENG Peiyu;SUN Shida;LIU Lei;XIANG Wang;WEN Jinyu(Electrical Power Research Institute of Henan Electric Power Corporation,Zhengzhou 450052,China;State Key Laboratory of Advanced Electromagnetic Engineering and Technology,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]国网河南省电力公司电力科学研究院,郑州450052 [2]华中科技大学电气与电子工程学院强电磁工程与新技术国家重点实验室,武汉430074

出　　处：《高压电器》2021年第6期179-188,共10页High Voltage Apparatus

基　　金：国家电网公司总部科技项目(52170218000M)。

摘　　要：文中研究了混合三端直流输电系统的直流故障特性及故障电流抑制策略。此系统送端为电网换相换流器(line commutated converter)、受端为混合型模块化多电平换流器(hybrid modular multilevel converter)。首先介绍了混合三端直流输电系统拓扑以及控制策略,随后针对不同故障点,不同过渡电阻以及不同故障类型的直流侧线路故障特性进行了仿真分析。同时,分析了直流故障下混合三端直流系统中混合型MMC故障过电流的产生机理,基于混合型换流器的优越控制性能针对系统故障暂态下过电流问题,设计了LCC和MMC的附加控制,抑制各换流器向故障点处馈入的故障电流;最后对混合输电系统不同区间下的架空线极对地故障进行了仿真分析,仿真结果表明,改进的控制策略能有效地抑制直流侧换流器馈入的故障电流。The DC fault characteristics and the fault identification method of hybrid three-terminal HVDC transmission system and fast suppression strategy of fault current are proposed.The system is composed of a line-commutated converter as the rectifier and two parallel hybrid modular multilevel converters as the inverters.Based on the model in PSCAD/EMTDC,the fault characteristics of pole-to-ground and pole-to-pole of the system at different locations are analyzed.In addition,the mechanism of hybrid MMC fault overcurrent in hybrid three-terminal DC system under DC fault is analyzed,to suppress the excessive fault current in the fault transient,additional control is set to the controller of LCC and MMC.Lastly,the simulation analysis of pole-to-ground fault in different positions of the system is carried out.The simulation results show that the improved control strategy can effectively suppress the fault current produced by the converters.

关 键 词：混合直流输电系统 多端直流输电系统 故障特性 故障电流抑制 

分 类 号：TM721.1[电气工程—电力系统及自动化]