模块化多电平矩阵换流器接入下的工频故障特性分析  

Analysis of Power Frequency Fault Characteristics Under Integration of Modular Multilevel Matrix Converter

作　　者：何佳伟[1] 魏杰 戴魏 李斌[1] 周博昊 吴通华 HE Jiawei;WEI Jie;DAI Wei;LI Bin;ZHOU Bohao;WU Tonghua(Key Laboratory of Smart Grid of Ministry of Education(Tianjin University),Tianjin 300072,China;NARI Group Corporation(State Grid Electric Power Research Institute),Nanjing 211106,China)

机构地区：[1]智能电网教育部重点实验室(天津大学),天津市300072 [2]南瑞集团有限公司(国网电力科学研究院有限公司),江苏省南京市211106

出　　处：《电力系统自动化》2024年第21期49-60,共12页Automation of Electric Power Systems

基　　金：国家自然科学基金杰出青年科学基金资助项目(52025071);国家自然科学基金资助项目(52207129)。

摘　　要：基于模块化多电平矩阵换流器(M3C)的柔性低频输电系统在中远海风电外送、异步电网互联等方面优势突出。然而,有别于模块化多电平换流器(MMC)等其他电力电子换流设备,M3C的控制策略将导致系统故障特性发生显著变化。现有将电力电子设备负序部分等效为开路的故障等值与响应特性计算方法无法适用。文中计及M3C正序定电容电压总平均值控制、负序电流注入控制以及环流控制分层构成的桥臂电容电压均衡策略,推导了工频侧线路故障以后,M3C输入输出功率均衡、桥臂功率均衡(电容电压均衡的必要条件)与正负序电压电流间的映射关系,由此构建了工频侧线路故障(不对称、对称)后的M3C输出电压电流响应特性的等效模型。在此基础上,提出了M3C接入下工频侧线路故障后电压电流响应特性的精确计算方法。最后,基于PSCAD/EMTDC仿真平台,搭建了海上风电柔性低频送出系统仿真模型,通过大量仿真算例充分验证了所提故障特性分析方法的正确性和精确性。The flexible low-frequency transmission system based on modular multilevel matrix converter(M3C)has outstanding advantages in medium-and far-offshore wind power transmission,and asynchronous grids interconnection.However,different from such power electronic converters as modular multilevel converter(MMC),the M3C control strategy may result in significant changes in system fault characteristics.The existing fault equivalence and response characteristic calculation method is not applicable,in which the negative-sequence component of power electronic equipment is equivalent to an open circuit.In this paper,the mapping relationship between the input/output power balance,the bridge-arm power balance(necessary condition for the capacitor voltage balance),and the positive-and negative-sequence voltage/current of M3C after system-side faults,is deduced considering the bridge-arm capacitor voltage balance strategy hierarchically composed of M3C positive-sequence capacitor voltage total average control,negative-sequence current injection control,and circulating current control.Thus,the equivalent models of M3C output voltage/current response characteristics after system-side faults(asymmetrical/symmetrical)are built.On this basis,the accurate calculation method for the voltage/current response characteristics after the system-side faults under the M3C integration is proposed.Finally,based on the PSCAD/EMTDC simulation platform,a simulation model of the offshore wind power flexible low-frequency transmission system is built,and the correctness and accuracy of the proposed fault characteristic analysis method are fully verified through a large number of simulation examples.

关 键 词：海上风电 低频输电系统 模块化多电平矩阵换流器 工频 不对称故障 电容电压均衡控制 

分 类 号：TM721.1[电气工程—电力系统及自动化]