A new fault location algorithm for radial distribution systems using modal analysis

In this paper, an accurate and efficient method is proposed for fault section estimation and fault distance calculation in distribution systems, based on frequency spectrum components of fault generated traveling waves. Fault occurrence in a radial distribution system generates high frequency traveling waves that can be divided into two parts. Part of them travels between fault location and substation and the other part is reflected between network junctions and substation. By identification of these two parts, the proposed algorithm determines faulted section and exact distance of fault from substation uniquely. Consequently, the main drawback of the impedance based methods which is the multiple-estimation problem is removed. In the proposed method, it is assumed that just one voltage recorder is installed at the distribution substation and additional equipments such as, fault indicators and PQ monitoring devices are also not needed to be installed in the distribution system. The simulations are carried out using ATP software and the results are processed by MATLAB software. Simulation results of various types of faults on a typical distribution system demonstrate high efficiency and accuracy of the proposed method. Effect of different influential parameters such as fault inception angle, fault resistance and load variations has also been taken into account.