南方电网技术2025，Vol.19Issue(7)：90-102,13.DOI:10.13648/j.cnki.issn1674-0629.2025.07.007
MMC-HVDC系统换流器桥臂保护的新方法
Novel Method of Converter Bridge Arm Protection in MMC-HVDC System
摘要
Abstract
An innovative converter bridge arm protection method is proposed for the modular multilevel converter-high voltage direct current(MMC-HVDC)system.Firstly,the current flow paths are analyzed when the single bridge arm of the converter is grounded and when the single-phase bridge arm is indirectly grounded.An equivalent circuit is constructed,and the expressions of the bridge arm current before and after the converter is locked are derived.Based on this,the unique characteristics of the sum of the three-phase bridge arm currents after a fault are analyzed,and a protection strategy is proposed to distinguish internal faults from external faults of the bridge arm by detecting whether the fundamental frequency components of the three-phase bridge arm and the current are zero.Given that the existing bridge arm protection methods cannot effectively deal with the short-circuit problem between single-phase bridge arms of the converter,the characteristics under such short-circuit conditions are further studied.It is found that the currents of the upper and lower bridge arms of the faulty phase only contain the fundamental frequency component and don't contain the DC component,and thus the corresponding action criteria are formulated.By outputting the short-circuit protection criterion between the three-phase bridge arm and current protection and the single-phase bridge arm through or gate,various faults oc-curring on the converter bridge arm can be comprehensively identified,enriching and improving the protection principle of the converter bridge arm.Finally,by building the simulation model of the bipolar MMC-HVDC system in MATLAB/Simulink,the ef-fectiveness and reliability of the proposed protection method are verified.关键词
MMC-HVDC/换流器桥臂保护/单桥臂/接地/短路/半周积分算法Key words
MMC-HVDC/converter bridge arm protection/single bridge arm/grounded/short circuit/half-cycle integral algorithm分类
信息技术与安全科学引用本文复制引用
张艳霞,马锦婷..MMC-HVDC系统换流器桥臂保护的新方法[J].南方电网技术,2025,19(7):90-102,13.基金项目
新能源电力系统国家重点实验室开放基金资助项目(LAPS23018).Supported by the State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(LAPS23018). （LAPS23018）
