Transmission grid fault diagnosis by wide area measurement system

While the importance of wide area measurement system (WAMS) consisting of phasor measurement units (PMUs) is recognized, there are still unidentified applications that can be addressed with the advance of technology. Traditionally, power system operators diagnosed the fault point through the status of protective relays and circuit breakers of the protection system. In large blackouts, however, the malfunction of protection system has itself often been among the suspects of the disaster. This paper proposes an alternative fault diagnosis approach independent of the function of protection system, utilizing PMU data and bus impedance matrix (Z_bus). First, the proposed method diagnoses the fault area, and next the fault line is diagnosed. Fault location along the diagnosed line is also estimated by wide-area measurements. The proposed method is applied to the IEEE 118-bus test system where the results indicate successful diagnosis of the faulted lines throughout the grid as well as wide area fault location along the faulted line.