基于VMD与HT分析的小电流接地系统故障选线技术分析  

Technical Analysis of Fault Line Selection for Small Current Grounding System Based on VMD and HT Analysis

作　　者：李晨 LI Chen(North China University of Water Conservancy and Electric Power,Zhengzhou 450000,China)

机构地区：[1]华北水利水电大学电力工程学院,河南郑州450000

出　　处：《电工技术》2022年第8期134-141,共8页Electric Engineering

摘　　要：配电网中小电流接地系统发生单相接地故障时,具有故障幅值小、噪声波动大等特点,导致线路电流变化特征不明显,采用传统选线技术又难以判断是线路故障还是母线故障。为了及时准确地判断线路故障,提出了一种基于VMD与HT分析的小电流接地系统故障选线新技术。首先利用Simulink搭建三种小电流接地模型——中性点不接地系统模型、中性点经消弧线圈接地模型及中性点经高阻接地系统模型。然后提取三种模型的零序电流进行VMD分解得到K个固有模态函数IMF,将分解得到的IMF通过HT分解得到每个模态相应的幅值谱图。最后通过算法逼近度计算每个模态相应的幅值,得到相应的算法逼近度系数,对比系数可以正确判断故障线路与非故障线路。结果表明,在三种不同接地模型中,基于VMD与HT分析的小电流接地系统故障选线新技术在不同故障距离、不同接地电阻情况下能够有效识别故障与非故障线路,具有一定的实用性。When the single-phase grounding fault occurs in the medium and small current grounding system of distribution network,the characteristics of small fault amplitude and large noise fluctuation lead to the unclear change characteristics of line current.It is difficult to judge whether it is line fault or bus fault by using traditional line selection technology.In order to judge the line fault timely and accurately,a new fault line selection technology of small current grounding system based on VMD and HT analysis is proposed.Firstly,three low-current grounding models are built using Simulink-neutral point ungrounded system model,neutral point grounding model via arc suppression coil,and neutral point grounding system model via high resistance.Then the zero-sequence currents of the three models are extracted and decomposed by VMD to obtain K intrinsic mode functions IMF,and the corresponding amplitude spectrum of each mode is obtained by HT decomposition of the decomposed IMFs.Finally,the corresponding amplitude of each mode is calculated by the algorithm approximation algorithm,and the corresponding algorithm approximation coefficient is obtained,and the comparison coefficient can correctly judge the fault line and the non-fault line.The results show that in three different grounding models,the new fault line selection technology for small current grounding systems based on VMD and HT analysis can effectively identify faulty and non-faulted lines under different fault distances and different grounding resistances,and has certain practicability.

关 键 词：小电流接地系统 变分模态分解 希尔伯特变换 算法逼近度 

分 类 号：TM732[电气工程—电力系统及自动化]