随着电网规模的不断扩大，电缆故障造成的影响和损失也愈来愈大。为了保障电力系统的正常运行，实现对电缆故障的快速、准确定位，电缆故障在线定位研究的重要性日渐凸显。本文以小波分析为理论基础，研究探讨了电缆故障的在线定位方法、电缆故障的系统建模、仿真数据的处理分析和虚拟仪器界面开发等方面的内容。 论文首先介绍了电缆故障的产生原因、类型和定位的基本原理，系统阐述了小波分析的基本理论和多分辨分析理论；然后以小波分析为理论基础，设计了电缆故障定位系统的总体结构，介绍了电缆中行波的传播规律，针对行波法故障测距中行波波速不定、波头难以寻找的问题，结合行波的折反射规律从理论上研究探讨了一种不受波速影响的故障定位算法；介绍了阈值去噪方法；研究了一种基于聚类的局部模极大值点寻找算法，用程序实现了行波波头的合理化寻找；建立了电缆故障定位系统的Simulink模型，对仿真数据进行了处理，分析和计算，验证了基于小波的电缆故障在线定位系统理论的正确性和可行性；最后，论文分三部分对故障定位系统的设计和实现情况进行了说明，介绍了信号调理模块、数据采集模块和上位机故障定位模块的工作目的和方法，并给出了用LabVIEW软件开发的虚拟仪器显示界面。

Cable is the aorta of the power system. With the development of electric power industry, the impact and losses caused by the cable fault become greater and greater. In order to safeguard the normal operation of the power system and locate the cable fault swiftly and accurately, the importance of the research on the online cable fault location is increasingly prominent. In this paper, the methods of the online cable fault location, system modeling, simulation data analysis and virtual instrument interface development are researched deeply based on the wavelet. Firstly, the causes, types and basic principles of location of the cable fault are introduced in this paper, and the basic theory of wavelet analysis and multiresolution analysis is systematically expounded. Then, the overall structure of the cable fault location system is designed based on the wavelet analysis theory. Next, the laws of traveling wave propagation are elucidated. For the uncertain speed of traveling wave and the difficulty to find wave head in fault location based on wave traveling method, an algorithm of cable fault location, which stands clear from the impact of wave speed, is studied theoretically based on the considering of the catadioptric law. Furthermore, the threshold denoising methods are introduced, an algorithm finding local modulus maxima point is proposed based on the clustering method, and the rational finding of the head wave of traveling wave is achieved by the programmes. The Simulink model of cable fault location is established and correctness and feasibility of the online cable fault location theory based on wavelet is verified by processing, analyzing and calculating the simulation data. Finally, the design and realization of fault location system are described in three parts in the paper. The purpose and methods of signal conditioning modules, signal acquisition module and PC fault location module are expounded. At the same time, the virtual instrument display interface developed with LabVIEW is shown.