随着城网、农网改造的深入，电缆的应用范围也越来越大。同时电缆发生的故障也不断增多。如何快速、准确地对电缆故障的种类、具体位置进行确定，对于提高电缆系统的供电质量、减小经济损失有非常重要的作用。而国内外较成熟的电缆故障测距方法大都基于离线状态，电缆在线故障测距,仍缺少有效的方法。因此，实现电缆在线故障测距，具有迫切的现实意义。本文以小波分析为基础，对电缆故障检测、故障采集与故障定位进行了研究，并研制了电缆在线故障采集装置。论文首先介绍了小波分析的基本概念，及小波分析检测奇异性的理论，并从多尺度分析及模极大值方法的角度出发，对小波变换在电缆线路的应用进行了研究；接着对输电线路的行波过程进行了阐述，通过采用相模变换的方法消除三相线路之间的耦合影响，在此基础上分析了行波在故障点、母线等阻抗不连续处的反射和折射情况，提出了不受波速影响的单端测距公式，在理论上消除了波速对故障测距精度的影响。用EMTP软件建立电缆故障系统模型，仿真算例表明选用小波变换作为时域频域分析工具，能够有效的对电缆故障暂态行波进行分析，且不受故障位置、故障类型及过渡电阻的影响，具有较高的测距精度。 论文随后根据电缆故障暂态行波的实际特点，完成了电缆在线故障采集装置软硬件的设计。硬件设计共分为3部分：一是由电流互感器和运放电路组成的信号调理电路；二是由TMS320LF2407A 作为主CPU的高速数据采集电路；三是由PC机作为系统的上位机实现数据分析、处理和存储等功能。软件设计共分为2部分：一是由C和汇编语言混合编写的下位机程序，主要完成系统初始化、中断采样、数据显示和数据通讯等工作；二是由VC语言和MATLAB语言编写的上位机分析软件程序，主要完成数据实时传输、数据文件保存、图形绘制、小波分析以及数据库开发等工作。最后对电缆在线故障测距装置进行了各项测试。测试表明，该系统硬件和软件设计正确，系统运行正常。

With the development of city and rural electric power network, the possibility of the cable fault accurate is also becoming more and more greatly. How do category and location of cable fault is ascertained quickly and accurately, for power system quality improvement of cable and reducing the economic loss to being the very influential role. The mature technology for cable fault location is mostly based on off-line at home and abroad. There are not efficient methods for cable fault location on-line, so this topic has an exigently realistic significance. This dissertation focuses on applying wavelet analysis to detect the time faults occurred, to gather cable fault and to calculate faults’ distance of cable.At first, this dissertation introduces the theories of wavelet, the singularity detection theories of wavelet analysis. The wavelet is applied cable fault location from the multi-scale analysis and module maximum, the wave course of transmission is introduced, the effect of coupling among three phase lines can be solved by phase-mode transform. The echo and refraction of traveling waves at the discontinuous spot of impedance, such as fault point or bus bar, are analyzed Aiming at the problem of the uncertainty of wave speed which influence the accuracy of location, fault distance expression that avoid the wave speed influence in theory are worked out, and model the cable fault by using EMTP software. simulation show that the wavelet transform can effectively analyze the transient traveling wave, and be immune to the fault location, fault type and transition resistance, and enhance the accuracy of location. Then the designing and application of the hardware and software of cable fault location system are performed in this paper. The hardware designing includes there parts: The first one is the signal adjustment circuit which is made of the current transformer and operational amplifier; The second one is high-speed sampling circuit which uses the TMS320LF2407A as the main center processing unit； The third one is PC computer as the upper computer of system. The software designing includes two parts: The first part is the front computer procedures which are compiled by C and assemble language that can achieve many works about system initialization, interruption acquisition, displaying data and transmitting data. The second part is the upper computer procedures which are compiled by VC language and EMTP that can accomplish some assignments about real time transmission of data, image-based rendering, file saving, wavelet analysis and data bank development. Finally, the system is tested in this paper. The test results show that the hardware and software can normal work and meet the requirements of cable fault location on line.