Harmonic power flow under non-sinusoidal conditions

Abstract

This article aims to analyze the electric field and the flow of electromagnetic energy in power cables with copper and aluminum cores, without considering the implicit physics of the coating that surrounds the conductor, which is generally composed of XLPE. Computational simulations were carried out with two models of alternating electrical current (AC) intensities, with a frequency of 60 HZ, electrical voltage of 1 kV, in a transient regime, with a phase difference of 120° and considering the lengths of the cables at a value of L = 30 m. Applying a Fourier series expansion to a sinusoidal electric current and expanding to the third term of the series, resulting in a new formulation of the electric current that was called modified electric current. The peculiarity of this research lies in the fact that, through the Fourier series expansion of conventional alternating current, a transformation to a modified current was observed, presenting behavior analogous to that of a Rectifying Diode. The improvements provided by this method include increased efficiency in the transmission of electrical energy, reduction of voltage drops, reduction of losses associated with the Joule-Lenz effect and extension of the useful life of the cable. The results demonstrated that, by modifying the electric current, the electric fields and Poynting vectors were calculated and approached the solutions of Maxwell's equation for conventional electric current, in both types of power cables. In addition, this approach has been observed to be particularly effective for power cables with a length of 30 m, and using the modified current in Maxwell's equations to compare the electric and Poynting fields with those calculated using conventional electric current. Therefore, the results obtained are satisfactory for both power cables.