## MATLAB小电流接地系统故障选线方法研究

Title   Research on Fault Feeder Selection Method in  Small-current Grounding System
Abstract
The non-effectively grounding method is widely used in the distribution network in China. When single-phase fault occurs in the non-effectively grounding system, the fault current is small and the system is allowed to maintain run 1~2 hours. However,  the increasing feeders and capacity make the current bigger than before, which is easy to cause two-phase shortcut and intermittent arc overvoltage complex，so it is important to select the fault feeder accurately. But because of the complex fault condition, the small fault current, additional current interference etc., it is difficult to select the fault feeder. 源`自<六:维;论-文>网/www.lwfree.cn
This paper introduces domestic and foreign methods of fault feeder selection, analyses the steady-state and transient characteristics of zero sequence current in ungrounded system and arc suppression coil grounding system when the single-phase fault occurs. Then the paper introduces the principle of wavelet packet theory, signal singularity and modulus maxima, and proposes the fault feeder selection and positioning method, using wavelet packet analysis. At last, model is set by the MATLAB software, and a number of experiments are set up, which proves that wavelet packet can be utilized to select fault feeder when single-phase fault occurs.
Keywords   the non-effectively grounding      wavelet packet
fault feeder selection       MATLAB
目 录
1  绪论    1
1.1  引言    1
1.2  研究现状    1
1.3    本文主要工作    1
2 小电流接地系统故障时刻的特征分析    3
2.1  中性点不接地系统单相接地故障电流稳态特征    3
2.2  中性点经消弧线圈接地系统单相故障电流稳态特征    4
2.3  接地故障暂态分析    5
2.4    本章小结    6
3  小波包分解原理    7
3.1  小波包分解介绍    7
3.2  信号的奇异性与小波变换系数模极大值    8
3.3  选线原理和流程图    8
3.4  本章小结    9
4  基于MATLAB故障选线仿真    10
4.1  中性点不接地系统故障运行    11 源`自<六:维;论-文>网/www.lwfree.cn
4.2  中性点经消弧线圈接地系统故障运行    22
4.3  中性点不接地系统小波分析    34 MATLAB小电流接地系统故障选线方法研究:http://www.lwfree.cn/zidonghua/20191001/40178.html
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