Earth fault location based on a Modified Takagi Method for MV distribution networks

In this paper, an earth fault location algorithm is developed for distribution networks with resistance-earthed neutral. The algorithm is actually a modified version of Takagi method which was initially applied for HV transmission lines. In the proposed algorithm, fault location is performed by means of a searching process on each homogeneous section of MV lines. The voltage and current information at the beginning of each section, which are needed for the process, will be estimated from measurements at the substation and the network parameters. To improve the accuracy, capacitances of underground cables are also taken into account in the fault distance formula. The simulation results on a CIGRE benchmark network are very encouraging, even with impact of distribution load uncertainty.