Accurate fault location algorithm for series compensated transmission lines

In this paper, an accurate fault location algorithm for series compensated power transmission lines is presented. A distributed time domain model is used for modeling of the transmission lines. The algorithm makes use of two subroutines for estimation of the fault distance-one for faults behind the series capacitors and another one for faults in front of the series capacitors. Then a special procedure to select the correct solution is utilized. Samples of voltages and currents at both ends of the line are taken synchronously and used to calculate the location of the fault. The proposed algorithm is independent of fault resistance and does not require any knowledge of source impedance. The proposed method has been tested using the EMTP/ATP model of a 400 kV, 300 km transmission line, which is compensated, by a three-phase capacitor bank in the middle. The results of computer simulation confirm the accuracy of the proposed method.