Sinusoidal steady-state analysis for fault location in power distribution systems

This paper studies fault location with single-ended measurement when a line-to-line short-circuit fault occurs in an overhead radial three-phase distribution wire. Sinusoidal steady state analysis based on the distributed-parameters model of the transmission wires is employed to locate a fault. By injecting two sinusoidal excitations with different frequencies to the faulted phases, measuring the voltages and currents phasors at the sending-end of the wire and solving certain nonlinear distributed-parameter equations, the distance and resistance of fault candidates can be determined. It is shown that the one has the minimum difference between the calculated fault distances or fault resistances under the two frequencies are the most likely actual fault point. A fault locator based on the proposed scheme is designed and implemented. The parameter measurements of wires as well as the receiving-end transformers in the field are studied. Simulation on the physical model of distribution wire shows that this fault location scheme works successfully.