利用故障电流首行波拟合的柔性直流输电线路单端行波保护原理  

Principle of Non-unit Traveling Wave Protection for VSC-HVDC Transmission Line Using Fault Current Initial Traveling Wave Fitting

作　　者：张晨浩 宋国兵[1] 董新洲[2] ZHANG Chenhao;SONG Guobing;DONG Xinzhou(School of Electric Engineering,Xi'an Jiaotong University,Xi'an 710049,Shaanxi Province,China;State Key Lab of Control and Simulation of Power Systems and Generation Equipments(Department of Electrical Engineering,Tsinghua University),Haidian District,Beijing 100084,China)

机构地区：[1]西安交通大学电气工程学院,陕西省西安市710049 [2]电力系统及发电设备控制和仿真国家重点实验室(清华大学电机系),北京市海淀区100084

出　　处：《中国电机工程学报》2021年第8期2651-2660,共10页Proceedings of the CSEE

基　　金：国家重点研发计划项目(2016YFB0900603);国家电网公司科技项目(52094017000W)。

摘　　要：基于电气量导数的行波保护方法在输电线路发生高阻故障时存在拒动问题。该文首先分析直流输电线路故障首行波特征,分别推导直流输电线路发生区内、外故障时保护安装处的故障首行波表达式。之后分析故障首行波表达式中各部分的物理意义,利用拟合的方法提取出故障首行波中反映故障位置而不受过渡电阻影响的指数系数。在此基础上,提出利用故障电流首行波拟合的柔直线路单端行波保护原理。仿真结果表明,拟合出的指数系数能够有效反映故障位置,所提出的保护方法能在1 ms内完成故障判别,并且具有高耐过渡电阻能力。同时分析验证了不同采样频率及噪声对保护方法的影响,结果表明所提出的保护方法对采样频率的变化和噪声影响具有高鲁棒性。The derivative-based traveling wave protection method has the problem of operation failure when high-impedance faults occur.In this paper,the characteristics of the fault initial traveling wave in DC transmission lines were analyzed first,and the expressions of the fault initial traveling waves at the protection installation site when internal and external faults occur were derived respectively.Then the physical meaning of each part of the fault initial traveling wave expression was analyzed,and the exponential coefficients reflecting the fault location not affected by the fault impedance were extracted by the fitting method.On this basis,the principle of non-unit traveling wave protection for VSC-HVDC transmission line using fault current initial traveling wave fitting was proposed.The simulation results show that the obtained exponential coefficient can effectively reflect the location of fault.The proposed protection method can complete fault identification within 1 ms,even with high fault impedance.Furthermore,the influence of the sampling frequency and noise on the protection method was analyzed and verified.The results show that the proposed protection method has high robustness to the change of sampling frequency and the influence of noise.

关 键 词：直流输电线路 故障首行波表达式 故障位置信息提取 故障电流首行波拟合 单端行波保护 

分 类 号：TM77[电气工程—电力系统及自动化]