The Fault Detection Research Of Power Cable

Due to many desirable characteristics electrical cable possesses, such as its limited floor space, reliable power supply, strong capacity of resisting disturbance, simplicity of management, time-saving maintenance, etc, it replaces overhead lines to transmit electricity in low-voltage distribution system gradually.Besides, it is also superior in its larger capacitance, which is of benefits to promote the power factor and stability of electrical grids. However, as electrical cables are often hanged in the air or buried deeply under the surface of earth or water, which means that it is highly elusive, it poses difficulties for searching,locating and maintaining the fault spots. An accidental breakdown would result in a long-time power outage, which has a detrimental impact on normal operation of businesses and ordinary people's daily life. Therefore, it is significantly crucial to do research on the methods of locating fault spots on electrical cables.Electrical cables are highly prone to abnormal malfunction in electrical power systems and its malfunction types are various. The environment of cable casting is usually harsh. With the advancement of technology, the fault diagnosis has already stepped into an era of microcomputer protection. Although the signals of power system relay protection are still analyzed and processed by Fourier,WT(Wavelet Transform) now is emerging as a novel data analysis tool, the applicability of which has already been proved in the study field of electrical power system.This paper is going to shed some lights on detection of fault spots on electrical cables with a study core of WT(Wavelet Transform) and travelling wave fault location to improve the accuracy and precision of detection. The research contents are presented in the following part:Firstly, by consulting related documents, the author deeply analyzed the development of fault location distance measurement, the rudimental factors of cable malfunctions and some solutions to this problem. There is also some research on the electrical characteristics of power cables, by which the basicelectrical parameter is revealed. Then by adopting WT(Wavelet Transform),this paper studies the basic theories and offers multistage analysis of WT. Using the best noise reduction method, the model maximum analysis and the course of noise reduction is provided by comparing and contrasting noise reduction methods of various threshold values. This paper points out the reasons of traveling waves being produced, the transmission characteristics of malfunctioned traveling waves, the most appropriate methods of locating fault spots. Finally, this paper constructs a simulation model of electrical cables fault location with MATLAB-STMULINK, obtaining valid signals by processing traveling waves with WT and realizing the detection of fault points with the means of traveling wave fault location.