Fault Line Selection in Non-solidly Earthed Network Based on Modulus Maximum Polarity

Despite the big progress made in recent years in the research on transient fault line selection methods in non-solidly earthed network, these methods are still far from perfect. A new scheme for fault line selection in non-solidly earthed network based on the singularity detection and modulus maximum polarity theory is proposed. This scheme applies wavelet packet transform to fractionize the frequency bands of the zero sequence transient current and picks out the characteristic band according to energy maximum principle. Not affected by line parameters and the neutral grounding manner, the criterion also has the ability of enduring high transition resistance. Its validity has been verified by the EMTP/MATLAB simulation results.