基于接地电流谐波特征的CT二次回路中性线接地故障辨识  

Identification of Neutral Grounding Fault in CT Secondary Circuit Based on Harmonic Characteristics of Grounding Current

作　　者：闫茂华 温才权 熊小伏[2] 荣浩 李大川 YAN Mao-hua;WEN Cai-quan;XIONG Xiao-fu;RONG Hao;LI Da-chuan(Wuzhou Bureau,U.H.V.Power Transmission Company,China Southern Power Grid Co.,Ltd.,Wuzhou 543000,China;School of Electrical Engineering,Chongqing University,Chongqing 400044,China)

机构地区：[1]中国南方电网有限责任公司超高压输电公司梧州局,广西梧州543000 [2]重庆大学电气工程学院,重庆400044

出　　处：《水电能源科学》2024年第10期201-205,共5页Water Resources and Power

基　　金：南方电网科技项目(CGYKJXM20220115)。

摘　　要：针对CT二次回路中性线发生接地故障,CT中性点接地电流幅值小难以识别中性线上的接地故障,发生区外故障时易诱发保护误动作的问题,提出利用CT中性点接地电流奇次谐波和偶次谐波的相对大小识别的中性线接地故障判据。在小电流、高噪声工况下,利用VMD-Prony算法通过VIMF模态分解和熵值排序,滤除中性点接地电流的高频噪声信号,并对低噪分量进行Savitzky-Gloay平滑,然后重构VIMF分量得到降噪信号,最后利用Prony算法获取谐波分量,用于中性点接地故障判别。现场测试数据和仿真数据验证结果表明,该判别方法具有可行性。It is difficult to identify the ground fault on the neutral line due to the small amplitude of the ground current at the CT neutral point,and it is easy to induce protection misoperation when an out-of-area fault occurs.A fault criterion for neutral line grounding is proposed based on the relative magnitude of odd and even harmonics of CT neutral ground current.Under the conditions of low current and high noise,the VMD-Prony algorithm is used to filter out the high-frequency noise signal of the neutral grounding current through VIMF mode decomposition and entropy sorting.The low mode component is smoothed by Savitzky-Gloay,and the VIMF component is reconstructed to obtain the noise reduction signal.Finally,the Prony algorithm is used to obtain the harmonic component for neutral grounding fault diagnosis.Finally,the feasibility of the discrimination method is verified through on-site testing data and simulation data.

关 键 词：CT二次回路 接地电流谐波 VMD-Prony算法 故障判据 

分 类 号：TM712[电气工程—电力系统及自动化]