Analysis of Factors Affecting the Relative Service Life of Transformers

Abstract

In hot climates, the ambient air temperature can reach 45 °C and more, which leads to heating of the windings of power transformers above the permissible values and, accordingly, to a reduction in their relative service life. The purpose of the study is to determine the values of relative service life and the factors affecting it for different loading modes of transformer 20/6 kV. The tasks of the study are: conducting an analysis of the composition of electrical consumers included in the industrial zone, for example, in the Syrian Arab Republic (SAR), developing a method for assessing the overheating temperature of transformer elements depending on the load factor $(\mathrm{K}_{\mathrm{L}})$ and environmental conditions, developing an algorithm for assessing the relative service life of transformers 20/6 kV and developing a simulation model in MATLAB for the electrical power system of industrial zone fed by substation 20/6 kV. The value obtained from the simulation shows an approximate agreement with the value of average temperature of heating windings of transformers 20/6 kV with an error not exceeding 1%. It has been proven that when installing compensating devices in an industrial zone, the loading factor of transformers 20/6 kV decreases from 0.80 to 0.75 and the heating temperature of the transformer windings decreases from 92 °C to 90 °C, therefore, the relative service life of transformers increases from 0.5 to 0.63.