Análise térmica de um transformador a seco na presença de harmônicos

Abstract

Currently the amount of nonlinear loads has been increasing significantly in the electrical system. They inject harmonic content into the power grid, damaging distributors and consumers alike. Among the damages to the transformer caused by the harmonics, for example, it is the decrease in performance and efficiency, malfunctions, additional losses, noise and also overheating. As a result, reduces the life of the insulation system, which is between the windings. This paper has the purpose of verifying the behavior of a 1 kVA three phase dry transformer in the presence of voltage and current harmonics. In the experimental study, the dry transformer was submitted to the sinusoidal voltage source and linear load, and another case with voltage source with harmonics (3rd, 5th and 7th orders) and nonlinear load. In each case the voltage and current waveform, transformer temperature (winding and core) and current THD were recorded.