基于相电流高频特征识别的配电网故障指示器原理.docVIP

基于相电流高频特征识别的故障指示器原理(华中科技大学) 湖北省武汉市 430074） 摘要 小电流接地系统单相接地故障的定位难点中不同级别的馈线故障相电流进行了理论及时频域分析，基础上借助于小波变换配电网特点故障相电流高频特征识别，提出了配电网故障指示器原理定位有哪些信誉好的足球投注网站算法与实现相比，该方案馈线处零序电流的获取，额外硬件投资，较强的实施性仿真结果证明该原理能够较好地的、及故障电压定位TM774 Study for Fault Indicator Based on the Faulty Phase Current Feature Recognition for the Distribution Network Tong Ning Yu Mengqi Lin Xiangning Zhang Rui Li Zhengtian （State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan 430074 P.R.China） Abstract It has been a hot issue for the fault location method in the neutral un-effectively grounded system (NUGS) when a single-phase earth fault occurs. In this paper, we start with the theoretical analysis and the time-frequency domain analysis for the faulty phase current in different level of the feeders, and a novel kind of fault indicator is put forward as well as the corresponding fault location algorithm. In comparison with the fault indicator that already exists, this new method does not rely on the zero-sequence current, and auxiliary hardware is not needed, which shows great feasibility. PSCAD/EMTDC based simulation results indicate that the proposed method is immune to the change of the neutral point characteristics, the fault resistance and the voltage. keywords：Distribution network, fault indicator, fault location, wavelet transform  1 引言 我国电压等级为~66 kV的配电网采用小电流接地方式，在于发生单相接地故障时能够内续运行，保障供电可靠性但另一方面，由于故障情形的接地电流较小，各种特征明显，选取故障地点定位的实现较为困难自动化技术了故障选线相关原理发展原始的1-3]只能用于故障选线定位故障位置，适应的如、，虽然考虑了消弧线圈的影响因素，4]。小波变换的提出的发展，单相接地故障暂态特征量的提取，故障线路的识别了可能5]。文献[5]提出了一种基于小波奇异性检测的小电流系统选线新方法，并利用验证学者故障暂态特征的自适应选线方案6-8]，提高了故障选线的可靠性，但无法适用于母线处只有两条馈线的情况 长久以来，小波变换在配电网中的应用研究仅涉及故障选线，，是但配电网中，的测量精度精确刻画零序电流的特征，保证结果的准确性9]。虽然近年来出现的10]与中电阻投切法11]为故障定位提供了完整的解决方案，但前者实现需高压较高及不稳定故障不敏感后者辅助硬件同时无法发挥单相接地故障情况下的稳定性优势12]，两者在实际应用中均有一定的局限性。配电网现有的及配置，接地故障情形下各级馈线处电流频谱极性特性进行推导及时频域分析；进而利用小波变换，模极大值法6]，对故障相电流中主导暂态电流性质的高频分量极性结合配电网结构原理利用软件验证其电阻消弧线圈投入状态故障时刻电压相位条件下的适应性。2 小电流接地系统单相故障特征分析2.1 故障理论分析 江西