Study Of Fault Location For Power Cable Of Passenger Dedicated Line

With the fast development of the high-speed railway in China, the safety and reliability of power supply for railway become more and more important. In this paper, the fault location methods are studied based on the characteristics of power cable of passenger dedicated line continuous lines.The characteristics of transient travelling wave are analyzed, based on the features of zero mode and aerial mode components, and the aerial mode component is chosen to locate fault. The existing problems of single-terminal location and two-terminal fault location were analyzed. And according to comparison of these two methods, the two-terminal fault location method is chosen for fault location. Based on the theory of travelling wave's refraction and reflection, the current travelling wave can't be detected, and the voltage travelling wave can be detected twice, so the voltage traveling is suitable for fault location.The detection of travelling wave's singular points is solved by using the theory of wavelet transform modulus maxima, and then the time demarcating of travelling wave on measuring point is solved. According to the parameters of power cable used in passenger dedicated line (DPL) and the frequency dispersion of traveling wave, and based on the frequency correlation of the lines, the formula of traveling wave speed can be derived. With this method, the error of wave speed is decreased based on the combination of center frequency and wave velocity.According to the design parameters of Wuhan-Guangzhou passenger dedicated line, the simulation model of its power cable is built by MATLAB. The grounding fault and short-circuit fault are simulated, then the feasibility and accuracy of two-terminal fault location method are proved, and this method has higher precision, it is appropriate for fault location of power cable used in passenger dedicated line.At last, a location of wave velocity insensitive is discussed. With this method, the influence of wave velocity is eliminated and the location precision is improved when fault happens at the far-end of power cable lines.