Antennas Comparison Applied to Detect Partial Discharges Coupled via Dielectric Window and Oil Valve in Power Transformers

Abstract

Considering increasing the reliability of electrical systems, continuous equipment maintenance is essential, thus ensuring longevity and avoiding 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 condition monitoring techniques for electrical equipment. One of these techniques is the detection of partial discharges in power transformers by means of antennas. Thus, different antennas were analyzed for different coupling to the sensor into the high voltage equipment, either via dielectric window or oil valve. In comparison, the L-probe antenna obtained the best result, at −10 dB, while at −5 dB the log spiral performed better, for insertion via the dielectric window. For coupling via oil valve, the monopole obtained the best result, at −10 dB, considering the bandwidth at −5 dB the conical 70 mm did better.