Efficient discrete wavelet representation of electrical power disturbances by measuring energy concentration in the tiled time-frequency plane

In this paper, it is proposed to treat the square wavelet coefficients as a probability density function in order to be able to measure energy concentration/dispersion in the tiled time-frequency plane. The proposed measure is the average distance to the center of mass of the tiled time frequency plane. This measure not only indicates energy concentration/dispersion in the tiled time-frequency plane but also hints that near symmetric orthogonal wavelets detect better the different electrical disruptions such as: transients, harmonics, interharmonics, voltage disruptions as well as sag and swell. To better illustrate the usefulness of the proposed approach a synthetic signal is generated containing the above mentioned electrical disruptions. The following wavelets are used to see which one concentrates better the energy in the tiled time-frequency domain: Daubechies, Coiflets, Symlets, Haar and the discrete Meyer wavelet.