Methodology for the identification of transient and permanent faults in overhead transmission lines, using wavelet transforms

Abstract

In this document an algorithm to detect and distinguish the transient and permanent faults, is developed. Also, the algorithm takes into account the determination of the secondary arc extinction time, to avoid effectively the monopolar reclosing onto faulty phase. The identification method is based on the frequency spectrum characteristics of the voltage waveform of the faulty phase before the operation of the breaker and the current waveform of a healthy phase. Both spectrums are correlated independently using a cross correlation ship. For the signal analysis the wavelet transform are used. The proposed methodology was tested in a electrical system with a nominal voltage of 380 kV, working right in all scenarios studied, reaching the right identification of the permanent or transient fault within the 25 ms after faults occurs.