A new impedance-based fault location method for radial distribution systems

A new impedance-based fault location method suitable for radial distribution systems is presented in this paper. The method uses the fundamental phasor components of voltage and current signals available at the distribution substation end only. Considering the unbalanced nature of the distribution network with single-phase and two-phase laterals, and unbalanced loads the fault location algorithm is derived using phase-component analysis. The multiple-estimation problem which is one of the main drawbacks of the one-end impedance based algorithms is solved in the present method using the estimated current information in the healthy phases. The methodology is based on the during-fault and pure-fault values of current phasors at the measuring end of the feeder and the distribution matrix derived using the pure-fault equivalent circuit. The efficacy of the method is demonstrated by simulating different distribution system configurations with different source impedances and fault types. The limitation of the proposed method is also discussed.