Detection and location of faults in large transmission networks using minimum number of phasor measurement units

Abstract

This paper presents an algorithm for detection and location of faults in large transmission network using the minimum number of phasor measurement units (PMUs). The transfer impedance between the fault point and the respective PMU buses, may be far away from the fault point, are used to define a non-linear set of voltage and current equations, which is then transformed into linear least square estimation problem where fault location is the unknown quantity. The algorithm starts by reducing the search area using a faulted bus identification index so as to speed-up the search process. Then considering all the transmission lines within the search area, a fault location identification index together with the fault location algorithm is used to identify the faulted line along with fault location. A PMU placement scheme, to find the minimum number of PMUs and their location, required for the proposed algorithm is also presented here. The proposed algorithm is tested and validated on the IEEE 14, 30, 39, and 118-bus systems for various fault conditions. Comparative results confirm that the number of PMUs obtained by the proposed placement scheme is minimum and sufficient for detection and location of faults irrespective of fault resistance and fault type.