Um estudo sobre tensões induzidas por descargas atmosféricas em linhas de transmissão

Abstract

The study of lightning and the resulting induced voltages is very important in the process of designing of transmission lines. In this work it will be presented problems that can be caused by such phenomenon in electrical systems, as a consequence of these voltages peaks. A analysis of the characterization of atmospheric discharge is performed in order to understand causes of induced overvoltages in transmission lines. Will be presented the classical methodology and a new proposal to estimate the tower surge impedance. In the new developed technique was used the finite element method, to obtain a computational model of the transmission tower, so as to simplify the studies. For the calculation of induced overvoltages, it was used the classic methodology developed by Sune Rusck, which is highly regarded and used for such propose. Based on the Rusck s theory, a computational model of induced voltages in transmission lines was implemented in EMTP/ ATPDraw environment, which it is a software developed by Hermann W. Dommel, with great application in evaluation of electromagnetic transients in power systems. From the model developed, results were obtained of induced voltages which are compared with measurements made by P. P. Barker, for checking and adjustment. Furthermore, propagation analysis of induced voltages on transmission lines were made, as well as the influence of some parameters in its amplitude and waveform.