Incorporating Goodness-of-Fit Metrics to Improve Synchrophasor-Based Fault Location

Abstract

This paper proposes to incorporate goodness-of-fit (GoF) metrics as outputs-in addition to the synchronized phasor (or synchrophasor)-from a phasor measurement unit (PMU) to assess the performance quality of synchrophasor-based real-time applications, with specific focus on the accuracy of fault location along a transmission line. Typically, a PMU outputs quantities that describe the phasor-of-best-fit of a time-domain voltage or current signal. While a phasor accurately represents the actual measured signal in sinusoidal steady state, this may not be the case during electrical transients that occur immediately after sudden events, such as a fault. Unaware of this, the real-time application may not locate the fault accurately. By quantifying the accuracy of the phasor as compared with the actual time-domain signal to which the phasor is fit, GoF metrics help to assess the credibility of fault-location results. This hypothesis is verified via extensive case studies, and GoF-based criteria for sufficiently accurate fault-location results are uncovered.