Single Phase Adaptive Autoreclosing Scheme Based on Continuous Wavelet Transform

This paper proposes an adaptive single phase auto reclosing scheme for EHV transmission lines using continuous wavelet transform (CWT). The CWT extract features from the faulted phase voltage waveform. The wavelet coefficients obtained by CWT can provide an effective signal representation of the voltage at the faulty phase. An index is derived by the sum of the energy of CWT coefficients. By assessing the index, temporary and permanent faults can be identified. In case of temporary fault, arc extinction instant can also be determined, which is used by protective relay to prompt auto reclosing signal. The reliability of the proposed algorithm is tested well under a diversity of fault conditions on a 500 kV, 320 km long overhead line using MATLAB/Simulink.