直流偏磁对二次谐波制动判据的影响及对策  

Influences of DC Bias on the Criterion for Second-order Harmonic Braking and the Corresponding Countermeasures

作　　者：陈争光 刘一民 王兴国 郑少明 李春波 邓丽虹 CHEN Zhenguang;LIU Yimin;WANG Xingguo;ZHENG Shaoming;LI Chunbo;DENG Lihong(China Electric Power Research Institute,Beijing 100192,China;State Key Laboratory of Power Grid Security and Energy Conservation,Beijing 100192,China;North China Branch,State Grid Corporation of China,Beijing 100053,China;Key Laboratory of Smart Grid of Ministry of Education,School of Electrical and Information Engineering,Tianjin University,Tianjin 300072,China;Beijing Jiaotong University,Beijing 100053,China)

机构地区：[1]中国电力科学研究院有限公司,北京100192 [2]电网安全与节能国家重点实验室,北京100192 [3]国家电网有限公司华北分部,北京100053 [4]天津大学智能电网教育部重点实验室,天津大学电气自动化与信息工程学院,天津300072 [5]北京交通大学,北京100053

出　　处：《电力系统及其自动化学报》2021年第5期91-99,共9页Proceedings of the CSU-EPSA

基　　金：中国电力科学研究院有限公司资助项目:柔性直流输电系统故障对抽蓄机组保护影响及孤岛运行时张北风电机组与直流系统协调配合策略(JBB51202000227)。

摘　　要：为防止直流偏磁对变压器差动保护的正确动作产生影响,提出了一种新的变压器差动保护算法来消除此影响。研究了高压直流输电单极-大地运行引发直流偏磁的机理,分析了直流偏磁对变压器工作状态和励磁电流的影响及直流偏磁引起差动保护二次谐波制动误闭锁的原理;针对有、无直流偏磁的情况,研究了变压器正常运行和发生区内故障时差动电流的电气特征,并进行了谐波分析,再以此为基础对传统差动保护进行了改进。仿真结果表明,改进后的保护算法消除了直流偏磁对二次谐波制动判据的影响。To prevent the influences of DC bias on the correct action of transformer differential protection,a novel transformer differential protection algorithm is proposed to eliminate these influences.First,the mechanism of DC bias caused by monopolar ground return mode of high voltage direct current(HVDC)transmission is studied,and the influences of DC bias on the working state and excitation current of the transformer are analyzed.In addition,the principle of second-order harmonic braking false blocking caused by DC bias is analyzed.Then,for the cases with and without DC bias,the electrical characteristics of differential current under normal operation and area fault of the transformer are studied,and the corresponding harmonic analysis is performed,based on which the traditional differential protection is improved.Simulation results show that the influences of DC bias on the second-order harmonic braking criterion are eliminated by the improved protection algorithm.

关 键 词：直流偏磁 二次谐波制动 励磁涌流 变压器差动保护 高压直流输电 

分 类 号：TM762[电气工程—电力系统及自动化]