A influência da disposição de fases nos campos elétricos de linhas de transmissão: uma análise comparativa entre sistemas trifásicos e hexafásicos

Abstract

Expanding electrical power transmission capacity is a necessary process to keep pace with recent growth in generation and increased consumption. Due to the difficulty of building new transmission lines, efforts are being made to increase the transmission capacity of existing lines. One possibility for this is to convert double-circuit three-phase lines to six-phase lines, an option that offers technical advantages when compared to commonly used alternatives. In this study, the impacts of the arrangement of the phases on the electric fields produced by the transmission line under these conditions are analyzed using the charge simulation method, which models the distribution of charges on the conductors as a number of discrete charges and allows the determination of electric fields at any point outside the conductors. A computer program was developed in Julia to apply the charge simulation method to transmission lines and was used, in particular, to study a tower with a double-circuit vertical configuration, simulating all possible arrangements for three-phase and six-phase systems. It was then found that the arrangement of the phases in the line considerably affects the electric fields both at ground level and on the surface of the conductors. Some six-phase configurations were found to be superior to all three-phase configurations in terms of the electric field on the surface of the conductors, but with a high electric field at ground level. Other six-phase configurations outperform all three-phase configurations in terms of the electric field at ground level, while also presenting satisfactory results in relation to the electric field on the surface of the conductors. It can therefore be concluded that, depending on the needs of each project, the transformation of a three-phase double-circuit line to a six-phase line requires the appropriate choice of phase arrangement in the conductors, which can reduce the electric field at ground level or on the surface of the conductors and, consequently, mitigate problems such as the Corona effect, one of the limiting factors in the design of extra-high and ultra-high voltage lines.