Lociranje parcijalnih pražnjenja u energetskom transformatoru primenom UHF tehnike

Abstract

A specially developed algorithm used in the program in MATLAB in a simplified model of a large power transformer will determine the locations of partial discharges using four UHF sensors by simulating ten real waveforms from a source of partial discharges. Subsequent interpolation of the recorded signals will be performed, in order to obtain the closest possible shapes to the actual waveforms. Actual waveforms were obtained by experimenting with a single UHF sensor in a real large power transformer. The ten signals of the actual shape are mutually different heights of the initial several peaks and different shapes, but still have similar maximum amplitude, frequency spectrum and the prevailing frequency of the most prominent partial discharges. It was important to determine where the actual signal begins, for which a unique calculation procedure was made, and later to accurately determine the differences between the occurrences of the first (reference) peaks of the actual signals at individual sensors. The most favourable threshold value was taken into account when determining the differences in signal arrival times by the method of the first acceptable peak. The deviations in the calculated positions of the sources of partial discharges obtained for 120 randomly selected points in the volume of the transformer tank model will be analysed.