Accurate estimating remote end equivalent impedance for adaptive one-ended fault location

Abstract

Fault location algorithms encounter error because of disregarding the fault current injected from remote end bus. In this paper, a one-ended method is proposed for determination of remote end fault current, in order to increase the accuracy of the fault location algorithm. This method is based on measuring the pre-fault voltage and current phasors from one side of the line without the need to employ communication link and data synchronization. Then a new formulation is applied to estimate Thevenin impedance from remote side of the line. The obtained equivalent impedance can be used to calculate accurate fault location. Using this method, fault location algorithm can be adapted to any network topology changes. For avoiding the effect of the other load variations on the estimation of remote end impedance, a new covariance based formulation is used. To clarify the effectiveness of the proposed method, it is applied on two sample test networks and the results are compared with three other methods. The simulation results show that the presented method in this paper is adaptive enough to the network topology changes and is robust against the network side load variations.