Análise de desempenho térmico de transformadores de potência com ciclo diário de sobrecarga planejada.

Abstract

The oil-immersed transformers are consolidated technology equipment; little change has been added to the projects over the last decades. A change of scenery for stronger growth of the Brazilian Electric Power System needs more powers and to follow this growth during a transitional period, the National System Operator decided in 2011 to require equipment able to withstand diary load cycle with long and short overloading of 20% and 40%. This requirement has direct consequences in the design of equipment, and also in the design of other equipment from these transformers connections in substations, like switch disconnectors , circuit breakers, current transformers and buses in older installations. Chesf transformers technical specification was changed in order to meet these conditions of overload. However, the study of the thermal behavior of power transformers deserves special attention since the design of the equipment. This work aims to evaluate the thermal design of power transformers from Chesf system acquired in the last two years, through the analysis of temperature curves of hot-spot. It is desired that the results will contribute and support the technical requirements of future technical specifications.