Especificação de disjuntores de alta tensão com base na superação por curto-circuito e tensão de restabelecimento transitória

Abstract

This paper presents the results of overstressing studies of circuit breakers in step-up substation of São Salvador, located in the state of Tocantins, based on the pre-operational data of 2008, supplied by ONS. In a very didactic way, the text explains about circuit breakers in general, about short-circuit and about overstressing methods. In the context of circuit breakers, items, such as functions constituent parts and processes of interruption, are discussed. About short-circuit, Fortescue’s theorem and the application of modeling the electrical system in symmetrical components for the follows types of short circuit, single-phase, two-phase, two-phase with the ground and three-phase, along with the explanation of different types of faults are presented. In the context of overstressing methods, there is a briefly explanation about overstressing due to charging current, due to short circuit currents symmetrical and asymmetrical, due to crest of current short circuit and due to transient recovery voltage (TRV). Based on short-circuit calculations and on simulations assisted by software, the overstressing studies of circuit breakers of the plant chosen are concluded.