Características do disjuntor para abertura de linha em vazio: metodologia de estudo

Abstract

This work presents a brief historical of the main factors responsible for standardized electric characteristics of circuit breakers used in the high and extra-high voltage in Brazilian Electric System. It describes the main types of overvoltages that define those characteristics, besides types and more relevant functions of circuit breakers supplied by the market. It describes study methodes usually adopted by the Brazilian Electric Utilities to find the requirements of the circuit breakers during no-load line switching, with emphasis in their advantages and disadvantages. The main product of this work consists to describe an alternative method, to analyse the phenomenon for no-load line switchig after load rejection, in order to provide reduction in the requirements of the circuit breakers and in its acquisition costs. Comparative analysis of the requirements are made for the circuit breakers of the Teresina Sobral-Fortaleza 500kV transmission line, part of the Chesf transmission system, for that phenomenon, using the proposed methodology and two other ones. Simulations are made with the Alternative Transients Program (ATP) in order to validate the methodology proposed. In syinthesis, this work describes a method to determine the requirements of overvoltage, current and frequency for circuit breakers during the process of line charging opening after load rejection, by means of simulations using digital program, Alternative Transients Program (ATP), and comparison the results with others obtained from two others methodologies commonly used by Brazilian Electric System Utilities.