All shunt fault location including cross-country and evolving faults in transmission lines without fault type classification

Abstract

This paper presents a fault location algorithm which does not need to classify the fault type before location estimation unlike some fault location methods. All types of shunt fault including the cross-country and evolving faults can be located and also faulty phase can be identified with this scheme. Cross-country fault is defined as earth fault occurring in different phases of same circuit at different location at same or different time. Further evolving faults are faults beginning in one phase and spreading to another phase after a few cycles. Finding the exact location of cross-country faults and evolving faults is not easy because the first involves faults at two different locations and the later involves change in type of fault after few cycles. The standard deviation of approximate DWT coefficients of three phase currents and voltages measured at one terminal of the line are used as input to proposed ANN algorithm. The simulation results show the efficacy and suitability of the proposed scheme under wide variety of fault situation and the percentage error in fault location estimation using the proposed scheme is within ±1% in most of the cases. The distinct advantage of the proposed scheme is that it accurately locates all the normal shunt faults, cross-country faults and evolving faults, which has not been dealt by other researchers simultaneously.