Análise de desempenho de pará-raios de ZnO sob diversos cenários de poluição utilizando método de elementos finitos

Abstract

Metal-Oxide Surge Arrester is one of the protection devices of vital importance for Electric Power Systems and the equipment that composes them, since it ensures the reliability and continuity of operation of these systems based on their ability to attenuate transient overvoltage resulting from lightning strikes or switching surges. This equipment is formed by blocks of variable ZnO resistors, associated in series or in parallel, whose voltage-current curve presents high non-linearity. In view of the relevance of using the lightning rod, it is necessary to investigate its operating conditions. In the literature, several procedures and techniques are found for this purpose, among which monitoring through measurement and analysis of the leakage current stands out, since this represents one of the main factors that contribute to the degradation of this equipment. Given this context, the present master's dissertation implements a two-dimensional model of a 30 kV Zinc Oxide lightning arrester, using the Finite Element Method, to obtain the leakage current curves, electrical potential distributions, current density and that of electric field lines, when this device is subject to voltage variations and pollution conditions. The results show a significant increase in these measured quantities as the level of pollution intensifies, as well as with the increase in voltage levels.