Study On The Online Cable Fault Location Analysis Based On Wavelets

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.