基于附加桥臂电流测量的非隔离型模块化多电平直流变压器差动保护方法  

Differential protection method based on additional bridge arm current measurement for non-isolated DC modular multilevel transformer

作　　者：王渝红[1] 谭子鹏 廖建权 刘洋涛 周念成[2] 王强钢 WANG Yuhong;TAN Zipeng;LIAO Jianquan;LIU Yangtao;ZHOU Niancheng;WANG Qianggang(College of Electrical Engineering,Sichuan University,Chengdu 610065,China;School of Electrical Engineering,Chongqing University,Chongqing 400044,China)

机构地区：[1]四川大学电气工程学院,四川成都610065 [2]重庆大学电气工程学院,重庆400044

出　　处：《电力自动化设备》2025年第5期161-167,共7页Electric Power Automation Equipment

基　　金：国家自然科学基金资助项目(52207126,U22B6006)。

摘　　要：直流变压器(DCT)的故障特性受内部储能元件及其拓扑的影响,传统基于端口电流差动的保护原理难以有效识别区内、外故障。针对非隔离型模块化多电平直流变压器(DCMT),提出了一种基于附加桥臂电流测量的改进差动保护方法。分析DCMT不同故障位置的故障电流特性,获得DCMT在区、内外故障下的差动电流特性,构建基于附加桥臂电流测量的DCMT差动保护复合判据。考虑到故障严重程度对故障识别的影响,结合比率制动原理,确定了DCMT差动保护阈值自适应整定策略。仿真实验结果表明,与传统方法相比,所提保护方法可准确识别DCMT内部匝间短路故障、端口母线故障和外部故障,在不同故障位置和故障电阻条件下有更高的灵敏性。The fault characteristics of DC transformer(DCT)are influenced by the internal energy storage components and their topologies,and traditional protection principles based on port current differential are difficult to effectively identify internal and external faults.A modified differential protection method based on additional bridge arm current measurement is proposed for nonsolated DC modular multilevel transformer(DCMT).The fault current characteristics of DCMT at different fault locations are analyzed,and the differential current characteristics of DCMT under internal and external faults are obtained.Subsequently,a composite criterion for DCMT differential protection based on additional bridge arm current measurement is constructed.Considering the impact of fault severity on fault identification,combined with the principle of ratio braking,an adaptive threshold setting strategy for DCMT differential protection is determined.The simulation experiment results show that compared with traditional methods,the proposed protection method can accurately identify the internal turn-to-turn short circuits,port bus faults,and external faults of DCMT.In addition,it has higher sensitivity under different fault locations and fault resistances.

关 键 词：直流变压器 故障 自适应保护 差动电流 直流分量 交流分量 

分 类 号：TM41[电气工程—电器] TM77