Impedance differential plane for fault detection and faulty phase identification of FACTS compensated transmission line

摘要

This paper presents an impedance differential plane (IDP) characteristic for the protection of Flexible AC Transmission Systems compensated transmission line using two-terminal synchronized measurements. The proposed algorithm identifies all shunt faults in the protected zone precisely. Restraint region is developed in a complex plane with the information of impedance ratio and their angle difference of both terminals to determine the short-circuit shunt fault in its zone of protection. In a complex plane, the y-axis stands for the impedance ratio, and the x-axis stands for angle difference. The proposed IDP characteristics evaluated in a three-machine with a detailed model of Unified Power Flow Controller (UPFC) and western system coordinating council nine-bus systems. The simulated test results prove increased sensitivity and reliability. The evaluation of IDP characteristic under different fault situations confirms its accuracy, selectivity, and robustness. Simulation study considers different operating modes of UPFC, compensation levels of UPFC, noisy conditions, and the CT and CCVT errors. Simulation studies bring out the superiority of the IDP characteristic.