Power quality disturbances segmentation based on wavelet decomposition and adaptive thresholds

This paper proposes an automatic method for determining an adaptive threshold based on Wavelet decomposition, which allows the segmentation of power quality signals. Primarily, these signals were synthetically generated, which represents short duration voltage variations, oscillatory and impulsive transients and harmonic distortions. Subsequently, the signals were decomposed by Daubechies Wavelets, whose second level of decomposition provided the values of energy and entropy of the energy used in determining the adaptive thresholds. The segments were then obtained by the intersections of the curves of Wavelets details with the calculated thresholds. The results reached with this methodology were evaluated under synthetic and real oscillographs in order to show its efficiency.