An autoregression-power based symmetrical fault detection during power swing

Distance relays are sensitive to the power swings. So these are blocked during power swing to ensure reliability of the power system. However, if a fault occurs during a power swing, distance relay must operate to clear the fault with a high degree of selectivity and sensitivity. This paper presents a new symmetrical fault detection techniques during power swing based on differential three-phase instantaneous power using auto regression. The differential three-phase instantaneous power is calculated from the difference of actual and predicted samples of three phase instantaneous power. The performance of the proposed method is verified by considering different fault conditions with varying fault resistances, fault inception times, fault distance and power angle. Simulation results in MATLAB environment show the efficacy of the proposed method.