基于特征频带暂态无功功率的配电网故障选线新方法  

A new method of fault line selection in a distribution network based on characteristic frequency band transient reactive power

作　　者：张玉玺 王增平 李振钊 徐潜 ZHANG Yuxi;WANG Zengping;LI Zhenzhao;XU Qian(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(North China Electric Power University),Beijing 102206,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京102206

出　　处：《电力系统保护与控制》2023年第1期1-11,共11页Power System Protection and Control

基　　金：国家自然科学基金重点项目资助(51637005);国家电网公司总部科技项目资助“新能源电力系统新型后备保护系统研究与应用”(5100-202199529A-0-5-ZN)。

摘　　要：为解决小电流接地系统在相电压过零点附近特征频带选取结果不准确、保护装置采样不同步等问题,详细分析了零模网络下配电线路的相频特性,并据此提出一种基于特征频带暂态无功功率相关性检测的选线新方法。首先,对各出线暂态零模电流与母线差分零模电压进行交叉小波变换,将二者相关性较强且相位差稳定的区域作为故障选线的时频窗。然后,利用时频窗内暂态电压电流信号的幅值与相位信息计算得到暂态无功功率。最后,根据特征频带内故障线路暂态无功功率与非故障线路暂态无功功率流向相反的特点,利用互相关函数算法对各出线暂态无功功率的相关性进行检测,确定故障线路。理论分析和仿真结果表明,所提方法不受故障初始角、同步误差、噪声干扰等因素的影响,对高阻以及弧光接地具有较强的适应性,且适用于分布式电源接入的配电网单相接地故障选线。The phase-frequency characteristic of a distribution line in a zero-mode network is analyzed in detail to solve the problems of inaccurate selection of characteristic frequency band near the zero crossing point of phase voltage and protection device sampling out of sync in a non-effectively grounded system.A new line selection method based on characteristic frequency band transient reactive power correlation detection is put forward in this paper.First,cross wavelet transform is carried out on each outgoing line transient zero-mode current and bus differential zero-mode voltage.The region with strong correlation and stable phase difference is taken as the time-frequency window of fault line selection.Then,the transient reactive power is calculated with the amplitude and phase information of the transient voltage and current signal in the time-frequency window.Finally,based on the characteristics that the flow direction of transient reactive power of fault line within the feature band is opposite to that of non-fault line,the correlation of transient reactive power of each outgoing line is detected with the cross-correlation function algorithm to determine the fault line.Theoretical analysis and simulation results indicate that the proposed method will not be affected by factors such as initial angle,synchronization error and noise interference of the fault,and has strong adaptability to high resistance and arc grounding.This is suitable for single-phase grounding fault line selection of a distribution network connected with a distributed power supply.

关 键 词：小电流接地系统 故障选线 特征频带 暂态无功功率 互相关函数 

分 类 号：TM862[电气工程—高电压与绝缘技术]