Interação entre transformadores de corrente de alta tensão e manobras do sistema

Abstract

In recent years, a great number of failures on current transformers have been recorded on the Brazilian power system. Such has led to the suspicion in which the electromagnetic transient is contributing for said failures, mainly when running on equipment that are fairly new in operation. For such equipment a great originator for these transients are the switching performed on the power system. Therefore, the aim of this work was develop a method to evaluate the effect of these high frequency transient imposed on the dielectric insulation of current transformers during circuit breaker and disconnect switch operation in the substation. For such, measurements were performed in laboratory to characterize the frequency domain on this equipment. This characterization is necessary for the method that will be used in the substation for the transient measurements. This is a practical and innovating method, developed during this work, that aims at facilitating this type of measurement. Based on the performed measurements, a procedure to evaluate the effect of these signals to the internal current transformer isolating system is investigate, in order identify if these signals can contribute to the loss of lifetime for these equipments.