A spatio-temporal processing Padé approach for visualizing harmonic distortion propagation on electrical networks

Abstract

This paper discusses the application of a spatio-temporal analysis method based on the Padé framework to analyze harmonic distortion in electrical networks. Using the observation matrix of three-phase voltage profiles, a polynomial in the z-domain is obtained for each profile. and their Padé approximation produces a discrete transfer function, which captures the dominant harmonics embedded in the signals. The application for a wide area of harmonic monitoring is proposed by extending the Padé approximant to the multi-signal case. By assuming that all signals have a common set of frequencies, the Padé approximation is efficiently computed for all the measurements. The best set of poles is extracted by the minimum singular value decomposition of an extended Hankel matrix. Due to its multiscale nature, the method is well suited for the analysis and monitoring of harmonic distortion in electrical networks. The developed methodology is compared with various analytical approximation methods using simulated noisy signals, proving that it is robust against the most common type of harmonic perturbations. Moreover, the proposed technique is applied to simulated data from a three-phase IEEE 14-bus test system, where the harmonic penetration and propagation is also discussed. Finally, the Padé method is validated on real measured signals.