Discrimination Between Power Swing and Faults in Series Compensated Transmission Lines Using the Piecewise Linear Spline Wavelet

Power swing may cause distance relays to operate incorrectly. Hence, this work presents a fast algorithm dependent on wavelet transform to differentiate a power swing from any fault that may occur in series compensated transmission lines. In this algorithm, the Piecewise Linear Spline Wavelet is used to analyze current/voltage waveforms into distinctive levels of frequencies. The eighth level of the single-phase current signal is used to identify power swing and thus to block the operation of the distance relay, whereas the first levels of the three-phase voltage signals are used to identify any fault case even in the presence of power swing, and thus to deblock the distance relay. To assess the efficacy of the presented algorithm, lots events of faults and power swings are examined on a test system modeled in MATLAB/Simulink. The results prove the advantages of the presented algorithm in terms of speed, reliability and efficiency.