From Available Synchrophasor Data to Short-Circuit Fault Identity: Formulation and Feasibility Analysis

Abstract

This paper proposes a novel formulation for determining the short-circuit fault identity, that is the fault type, faulted line, and exact fault distance on it, by using available synchrophasor data. A simple and yet quite effective procedure is developed to model the fault area as a stand-alone sub-system. Thanks to phasor measurement units (PMUs), the proposed technique does not require the operating point and model of the portions being replaced. This greatly alleviates the complexity and technical problems involved in modeling the entire power system, as enforced by existing wide-area methods. A couple of effective theorems in Circuit Theory are exploited in a way as to make the prefault bus impedance matrix applicable in the postfault condition. The obtained fault equations are readily solved by the least-squares method to provide a closed-form solution for the fault distance. Two necessary and sufficient conditions are introduced to assess the fault location feasibility by any given set of PMUs. High accuracy is achieved since the calculations merely involve sound equations remaining after removing erroneous measurements of instrument transformers. The proposed method is successfully validated by more than 10 000 simulation cases conducted on the New England 39-bus and 118-bus test systems.