基于小波变换的电力电缆故障检测研究

电气工程论文编号:DQ181   论文字数:23208,页数:50

目录
摘 要 I
Abstract II
目录 III
1  绪论 1
2  电力电缆故障分类 4
2.1 电缆的组成结构 4
2.2 形成电缆故障的原因分类 4
2.2.1 机械损伤 4
2.3  电力电缆故障分类 6
2.3.1 按电缆的组成材料分类（物理属性） 6
2.3.2 按电缆故障发生的原因分类 8
2.3.3 按电缆的结构特性分类 9
2.3.4 按电缆故障发生的部位分类 9
2.3.5 按故障外表特性或人的直觉性分类 10
2.3.6 按电缆损坏程度分类 10
2.3.7 按电缆的耐压等级分类 11
3  常见故障检测方法 12
 3.1 电缆故障点的粗测 12
3.1.1 直流电桥法测量短路和接地故障 12
3.1.2 脉冲反射法测量电缆故障 16
3.2 电缆故障点的精测(定点) 19
3.2.1 声测法 19
4  小波分析理论 24
4.1 小波变换的基本概念 24
4.1.1 基本小波 24
4.1.2 小波基函数 25
4.1.3 连续小波变换 25
4.1.4 离散小波变换 26
4.2 常用小波函数 26
4.2.1 Haar小波 27
4.2.2 Daubechies(dbN)小波 28
4.2.3 Coiflet(coifN)小波 28
4.2.4  Symlets(symN)小波 29
4.2.5 Mexican Hat(mexh)小波 30
4.2.6 Meyer小波 30
4.3 MATLAB算法 30
4.4 小波变换模极大值与奇异性检测 32
5  基于小波分析的电缆故障在线定位检测的设计与仿真 35
5.1 基于小波的电缆故障在线定位系统描述 35
5.1.1 小波分析在输电线路奇异点检测中的应用 35
5.2 电缆故障在线定位系统仿真 36
5.2.1 建立电缆故障系统模型 36
5.2.2 电缆断路故障仿真模型 37
5.2.3 断路故障的数据分析计算 37
5.2.4 电缆短路故障仿真模型 39
5.2.5 短路故障的数据分析计算 40
6  总 结 43
致 谢 44
参考文献： 45

摘 要
 随着国民经济的快速发展，我国电力工业得到了迅猛发展。电网规模越来越庞大，城市配电网络结构日益复杂完善，电力电缆的应用日益增多，电力电缆故障也相应增多。而输电线路电压等级和输送容量的逐步提高使得输电线路故障对社会经济生活造成的影响和损失也越来越大。因此如何尽快探测故障点距离，尤其是如何快速准确地找出电缆故障点并尽快修复，对配电网运行维护人员来讲是一项颇为艰辛的任务。目前，线路保护己经进入微机保护时代，而小波变换作为新型的更有效的数学分析工具，己在电力系统中得到应用。
 本文将采用小波变换快速算法对电力系统中故障信号进行分析、判断。仿真结果表明，这种算法能够准确及时判断故障，符合工程实时性的要求。和传统方法相比：利用了小波的带通滤波性质，减少了信号损失，简化了检测系统硬件电路。此方法实现容易，信号分析效果好。
 
 
关键词：小波分析、电力电缆、故障波形、检测波形

Abstract
With the rapid development of the national economy, our national power industry also has been developing fast. The larger the size of the grid, the more complex and advanced the power distribution network, the larger the application of power cable, the more the power cable fault. The gradually improvement of the voltage classification of transmission line and the transmission capacity leads to greater influence and loss to the social and economic life caused by transmission line fault. Consequently, how to detect the point of fault as soon as possible, especially how to identify exactly and quickly repair the cable fault, is a rather difficult task for the operation maintenance personnel of power supply. At present, the railway protection is approaching into the microcomputer protection era, while wavelet transform, as the innovative and the most effective mathematical analysis tool, has been widely applied in the power system.
This thesis is adopting the wavelet transform fast algorithm to analyze and judge the fault signal of power system. The emulation results show that this formula can judge and locate the fault precisely and timely, which conforms to the requirements of real-time project. Compare with traditional methods, this method uses the band-pass filter qualification of the wavelet, and decreases the signal loss, simplifies electrical circuit of detecting hardware system. This method is easy to accomplish and boasts a great effect of signal analysis.

Keywords：wavelet analysis、 power cables、fault waveform、the waveform detection