摘要
谐振接地系统在不同故障条件下发生单相接地故障时,故障信息十分微弱,给故障检测带来了极大的困难。但故障馈线与健全馈线的短时窗暂态零序电流时频域分布特性存在差异,利用S变换强大的时频分析能力对单相接地故障下零序电流的暂态特性进行了分析,以各馈线中暂态零序电流在不同频率下不同时刻的特征差异为依据,构造零序电流幅值时频矩阵,在综合考虑多种频率信息、突显时频局部特征的基础上,提出了一种基于S变换时频特性的故障选线新方法。该方法弥补了传统选线方法仅基于单一特征频带涵盖信息不足以及各馈线特征频带不一致的缺陷,结合图像处理相似度原理,通过综合相关系数实现配电网谐振接地系统单相接地故障选线。仿真结果表明该方法受故障位置、故障电阻、故障初始角、网络结构的影响较小,对不同故障接地类型都能进行有效判别,故障边界明显,可靠性好,抗干扰能力强,适用性更广。
When single-phase grounding fault occurs in resonant grounded system in different fault conditions,the fault signals are very weak,which makes it difficult to detect the fault.According to the differences in characteristics of transient zero sequence current of short-time window time-frequency,the transient characteristics of the zero sequence current of single-phase earth fault is utilized and analyzed in this paper by S transform,where the zero-sequence current amplitude time-frequency matrix can be constructed based on these differences in characteristics.On the basis of multiple frequency information and local characteristics of time-frequency,a new method of fault line selection based on S-transform time-frequency characteristics is proposed in this paper.This method can be applied in the scenarios with the lack of information coverage in a single feature band and the inconsistent band characteristics of each feeder.Combined with the similarity assessment of image processing,the single-phase ground fault line selection for a resonant grounding system of a distribution network can be achieved by comprehensive correlation coefficients.The simulation results show that the new method will be less affected by fault initial angle,fault resistance,fault location and network structure.It can effectively distinguish different fault grounding types,and has obvious fault boundary,high reliability,strong anti-interference ability,and more extensive applicability.
作者
蔡军
周波
黄跃
曾祥君
CAI Jun;ZHOU Bo;HUANG Yue;ZENG Xiangjun(Changsha Power Supply Branch, State Grid Hunan Electric Power Co., Ltd., Changsha 410015,China;Hunan Province Key Laboratory of Smart Grids Operation and Control,Changsha University of Science & Technology,Changsha 410114,China)
出处
《电力科学与技术学报》
CAS
北大核心
2022年第3期109-116,共8页
Journal of Electric Power Science And Technology
基金
国家自然科学基金(52037001)。
关键词
配电网
谐振接地系统
故障选线
S变换
时频特性
distribution network
resonant grounding system
fault line selection
S-transform
time frequency characteristics
