The Research On Fault Location In Distribution Network

In our country neutral non-effectively grounded mode is adopted mostly in distribution network. When single-phase ground fault happened fault current is relatively smaller so it is difficult to locate the fault point. The traditional fault location method is realized by people through searching along the lines. However as the electricity reliability requirements continue to improve the traditional positioning methods can not meet users’needs any more. So it is urgent to find a fast and accurate positioning method.After comparing the advantages and disadvantages of various positioning methods the paper choose the traveling wave method as the main study object. The traveling wave method based on the mechanism of wave’s refraction and reflection in line’s impedance discontinuity. The problem on the traveling wave method’s application in distribution network reflected in two aspects. One is about the wave’s attenuation and another is about pseudo fault point. For the first problem the paper proposed to discuss respectively for each line. This method reduces the wave attenuation by reducing the number of branch points which the wave getting through. For the second problem the paper proposed to use double-ended location method to determine the fault branch. This method can determine the point of failure uniquely in theoretically. Keeping the wave’s velocity constant in lines is a precondition in traditional traveling wave method. But the velocity of wave varied widely in overhead lines and cable lines and this lead to the failure of the traditional traveling wave fault location method. For this problem the paper proposed a fault search algorithm based on the variable of time. The effectiveness of all the methods is proved by ATP simulation.