Comparação entre antenas aplicadas a detecção de descargas parciais acopladas via janela dielétrica e válvula de óleo em transformadores de potência.

Abstract

In order to increase the reliability of the electrical systems, continuous equipment maintenance are essential, thus, their longevity, avoiding eventual failures, that can cause irreparable damage to the equipment. Partial discharges are physical phenomena that cause short circuits in power equipment. There are techniques that use the detection of partial discharges as a way of monitoring equipment. One of these techniques is the detection of partial discharges in power transformers through antennas. Thus, the study and development of antennas with this application is of great value, as it can prevent eventual failures arising from this phenomenon, which is the object of study of this project. Thus, different antennas has been analyzed for different ways of inserting the sensor into the high voltage equipment, either via dielectric window or oil valve. Into the case for the microstrip antennas, bandwidth optimization techniques has been applied in the antennas, aiming to fill relevant maximum UHF (Ultra High Frequency) band where partial discharges occur, corresponding to the interval between 0.3 GHz and 1.5 GHz. Therefore, several simulations has been carried out that allowed a comparison between the insertion methods and also the antennas. Being able to conclude which are the best techniques to be used, in order to maximize efficiency, without forget to reduce the dimensions of the antennas. For comparative purposes, antenna Sonda em L has obtained the best result for insertion via dielectric window, while in the case of coupling via oil valve, antenna monopole has obtained the best result, thus enabling the use of different antenna’s model for different ways of application.