MMC子模块IGBT开路故障诊断策略  

IGBT Open-Circuit Fault Diagnosis Strategy for MMC Sub-Module

作　　者：郭彦勋 李海锋[1] 李健涛[1] 洪潮 陈雁 王钢[1] 钟庆[1] 

机构地区：[1]华南理工大学电力学院,广州510641 [2]直流输电技术国家重点实验室(南方电网科学研究院),广州510663

出　　处：《南方电网技术》2017年第7期51-57,共7页Southern Power System Technology

基　　金：国家自然科学基金资助项目(51577072)~~

摘　　要：模块化多电平换流器(modular multilevel converter,MMC)内部子模块发生故障的概率较高,快速准确地检测、定位、隔离故障子模块可有效改善换流站运行条件,避免不必要的停运。本文提出一种基于滑模观测法的子模块绝缘栅双极型晶体管(insulated gate bipolar transistor,IGBT)开路故障诊断策略,在分析子模块IGBT开路故障特性的基础上,以桥臂电流为观测量搭建滑模观测器,快速检测子模块IGBT开路故障;利用桥臂电流测量值与计算值的差值及其变化率识别子模块故障类型;根据不同的故障类型选取部分子模块,计算子模块电容电流的理论值与实际值的比值,实现故障定位。最后在PSCAD/EMTDC中搭建了MMC-HVDC系统,仿真结果表明所提策略能有效减小故障定位的运算量,快速检测出IGBT开路故障,并准确定位故障。The fault probability of sub-modules in modular multilevel converter （MMC） stays at a high level, fast and precise diagno- sing and isolating the faulted sub-modules are critical for MMC to improve the operation conditions of converter and avoid unnecessary outages. Based on analysis of open-circuit fault characteristics of insulated gate bipolar transistor （IGBT） of sub-modules, a sliding mode observer is constructed to observe arm current and detect swiftly open-circuit fault in IGBT sub-module. By using the difference and changing rate between the measured value and the calculated value of arm current, fault type of the sub-module can be distinguish- ed, relevant part of the sub-modules is selected according to the types of fault, then by calculating the ratio of the actual value against the theoretical value of the current flowing through sub-modules, the faulted sub-module can be located. Simulation on an MMC- HVDC system established on PSCAD/EMTDC shows that the proposed fault diagnosis method can reduce the computation of fault lo- cation effectively, detect and locate IGBT open-circuit fault accurately and swiftly.

关 键 词：模块化多电平换流器(MMC) 子模块故障特性 滑模观测 故障诊断 

分 类 号：TM712[电气工程—电力系统及自动化]