Adaptive Single Phase Autoreclosing Scheme for EHV Transmission Line

Efficient protection system plays a vital role in power system stability by detecting and eliminating the faults quickly on overhead transmission lines. Temporary fault is the most frequent fault type that appears on high voltage (HV) and extra high voltage (EHV) lines which are followed by secondary arcs. Consequently adaptive single phase autorecloser (ASPAR) is the need of the time to get rid of temporary faults. Continuous wavelet transform (CWT) with fast Fourier transform (FFT) algorithm (CWTFT) is presented in this paper which utilises faulted phase voltage waveform and obtain wavelet coefficients after the circuit breaker isolate the faulty phase. Depending on the energies of the wavelet coefficients, a threshold is defined. In case of a transient fault, the coefficient energies exceeds the threshold level after the arc extinction and are well recognised by the proposed algorithm. This fact is used to initiate a safest reclosing in case of a temporary fault otherwise autoreclosing will be blocked. To appraise the efficiency of the presented algorithm, laborious simulations have been performed for a diversity of fault conditions i.e. at different fault locations, load angles and fault resistance, where in all cases, maximum consistency has been achieved.