Identification and Classification of High Impedance Faults using Wavelet Multiresolution Analysis

This paper presents an application of Wavelet multiresolution analysis (MRA) for the identification and classification of high impedance faults. Daubechies eight (D-8) Wavelet transforms of three phase currents on transmission lines are used for the analysis. The peak absolute values, the mean of the peak absolute values and summation of the 3rd level output of MRA detail signals of current in each phase extracted from the original signals are used as the criterion for the analysis. Different types of transients are considered based on this criterion for identification purpose and a threshold level is determined for peak absolute value and mean of the peak absolute values to differentiate a high impedance fault from other types of transients. Similarly, different types of high impedance faults are considered for classification purpose and a simple characteristic relationship is found for each type of fault using the summation of values of 3rd level wavelet output. The effects of fault distance and fault inception angle are also examined. Extensive simulations are carried out on a 400kV, 300km long line and simulation results show that the method is simple, effective and robust for the analysis of high impedance faults.