Threshold-based Power Grid Fault Diagnosis

This paper presents a threshold-based approach for power grid fault diagnosis in a power system based on correlation between fault types and basic measurements. The main focus is on faults that may occur on transmission and distribution lines due to uncontrolled events. The proposed method utilizes simple voltage and current measurements in transmission lines to extract divergence of these measurements from typical or nominal values. The first phase of the method is similar to a "training" phase where thresholds are identified for each measurement, followed by the second phase where binary combinations of comparisons with thresholds are used to diagnose specific faults. The IEEE standard 14-bus system is used to illustrate how the proposed method can be applied for transmission line fault diagnosis. Two-and three-phase to ground faults in three transmission lines are injected in a simulation platform as an example, and their effect on different current measurements are observed. Two basic quantities are observed for each of the measured signals: 1) RMS value, and 2) harmonic content. Measured quantities are shown to accurately capture unique binary signatures of different faults so that they can be utilized in offline and/or online fault diagnosis.