Estudo de saturação de transformadores de corrente aplicados em sistemas elétricos de potência

Abstract

This paper presents a study of current transformers (CTs) saturation applied in electric power systems through the development of a graphical interface via Matlab together with the software of transients simulation ATP. Initially, did it a brief explanation about the operation of a current transformer considering the normative ABNT NBR 6856, besides the dimension and short circuit criteria. From that, started the graphical interface development that allows by simulations for different conditions of short circuit level, voltage level and burden, observes the secondary winding behavior of the CT through a wave graphic reflected on the primary winding from the same and conclude if there was saturation in the current transformer’s core. Furthermore, an approximate saturation curve by the voltage knee method according to the CT’s exactness class could be estimated in case of the saturation curve tested from the current transformer is not available. For simulations that have a tested saturation curve, the interface will allow the insertion of these data to consider during simulations. The created interface allows, in a simple and clear way, the analysis of operational conditions that might lead the current transformers to the saturation of its cores, streamlining thus, the decisions taking inherent to the engineer.