摘要
变电站直流系统的状态直接关系到变电站的正常运行,为了对变电站直流系统出现的接地故障快速、准确定位,提出了一种双树复小波变换(DT-CWT)和奇异值分解(SVD)相结合的变电站直流系统接地故障检测新方法。该方法首先利用DT-CWT对支路电流信号进行分解来构建Hankel矩阵;然后对Hankel矩阵进行SVD分解,得到一系列奇异特征值;再次,利用相邻奇异值差值构建奇异值差分谱,通过奇异值差分谱最大峰值来保留有效的奇异值个数;最后,利用保留的奇异值来重构低频信号。算例分析结果表明,该方法能够准确地从支路电流信号中提取出低频交流信号,可以对变电站直流系统接地故障进行准确定位,很大程度上减小对地电容对检测精度的影响。
The state of the DC system of substation is directly related to the normal operation of the substation.A new method for ground fault detection in substation DC systems,which is a combination of double-tree complex wavelet transform and singular value decomposition,was proposed to achieve fast and accurate location of ground faults occurring in substation DC systems.Firstly,the method constructed a Hankel matrix to decompose the branch current signal through a dual-tree complex wavelet transform(DT-CWT).Secondly,the Hankel matrix was decomposed by the singular value decomposition(SVD)method with the aim of obtaining a series of singular eigenvalues.Thirdly,the singular value difference spectrum was constructed using the adjacent singular value differences,and the number of singular values was retained by the maximum peak of the singular value difference spectrum.Finally,the low-frequency signal was reconstructed by the retained singular values.The analysis results of the algorithm show that the method can accurately extract the low-frequency AC signal from the branch current signal and achieve the accurate location of the DC system ground fault in the substation,which can largely reduce the influence of the ground capacitance on the detection accuracy.
作者
李能俊
杨海成
许显科
李书山
高玉玲
LI Nengjun;YANG Haicheng;XU Xianke;LI Shushan;GAO Yuling(State Grid Qinghai Electric Power Co.,Ltd.Xining Power Supply Company,Xining 810000,Qinghai,China;Power China Qinghai Electric Power Engineering Co.,Ltd.,Xining 810000,Qinghai,China)
出处
《电气传动》
2024年第5期80-85,共6页
Electric Drive
基金
国网青海省电力公司管理科技项目“变电站直流系统故障监测隔离与辅助运维技术研究”(522801220002)。
关键词
直流系统
接地故障检测
双树复小波变换
奇异值分解
DC system
ground fault detection
double-tree complex wavelet transform(DT-CWT)
singular value decomposition(SVD)
