基于行波高频分量互相关函数离散度的高压直流线路双端保护方法  

Two-terminal Protection Method for HVDC Transmission Lines Based on High-frequency Cross-correlation Function Dispersion of Traveling Wave

作　　者：张腾跃 韩昆仑[1] 陈锋元 杨东睿 宋世勇 ZHANG Tengyue;HAN Kunlun;CHEN Fengyuan;YANG Dongrui;SONG Shiyong(Guangxi Key Laboratory of Power System Optimization and Energy Technology,Guangxi University,Nanning 530000,China)

机构地区：[1]广西大学广西电力系统最优化与节能技术重点实验室,南宁530000

出　　处：《高电压技术》2023年第3期1254-1262,共9页High Voltage Engineering

基　　金：国家自然科学基金(51567003)。

摘　　要：直流线路边界对故障暂态电流信号高频部分具有衰减作用,对于双极线路而言,健全极感应行波高频分量小于故障极。据此提出一种基于行波高频分量互相关函数离散度的高压直流线路双端保护方法,将线路保护与故障测距结合起来。首先,利用离散小波变换(discrete wavelet transform, DWT)将双极直流线路故障电流波形进行四层分解,得到高频细节分量。随后,对健全极与故障极的双端高频细节分量分别进行互相关分析。最后,通过互相关函数的离散度判断故障区与故障类型,并可通过互相关函数极大值坐标初步计算故障距离。在PSCAD/EMDTC中搭建仿真模型,实验结果表明该方案可有效判断故障类型并同时进行故障测距,不受过渡电阻影响。The DC transmission line boundary may attenuate the high frequency part of the fault current travelling wave.And for bipolar transmission lines,the high frequency content of the healthy pole induction traveling wave is less than that of the fault pole.This paper presents a novel two-terminal protection method of HVDC transmission lines based on high-frequency cross-correlation function dispersion degree of traveling wave,combining line protection and fault loca-tion.Firstly,discrete wavelet transform(DWT)is used to decompose the fault current travelling wave of bipolar DC lines into four layers and obtain high frequency detail contents.Secondly,the cross-correlation coefficients between high fre-quency detail components of fault pole and healthy pole is calculated.Finally,the fault zone and fault type are determined by the dispersion of the cross-correlation function,and the fault distance can be preliminarily calculated by the maximum coordinate of cross-correlation function.The simulation model is built in PSCAD/EMDTC,and the experimental results show that the criterion can effectively judge the fault type and calculate fault location,which is not affected by transition resistance.

关 键 词：直流输电 互相关性 离散小波变换 线路保护 故障识别 离散度 

分 类 号：TM773[电气工程—电力系统及自动化] TM721.1