Aging Performance of Transformer Oil Insulation-State of Art Review

The objective of this review paper is to understand the aging aspects of the transformer insulating oil by studying the aging performance of two widely used liquid dielectrics ie., mineral oil and natural ester oils along with paper as solid insulation. The performance of the power transformer is mainly decided by the proper working of its insulation. Thus monitoring the performance of insulating oil with aging results in more reliable working of the transformers. Here the aging mechanism of the insulating oil is briefly discussed alongside various study done in understanding the aging performance of both the liquid dielectrics using various methods and thus the degradation rate of both the dielectrics are examined. Naturally available ester oils are found to have better performance in comparison to mineral oil and also the paper degradation rate was found to be slower in these ester oils. Various methods used in monitoring the aging phenomenon are discussed briefly which compares the aging markers of both the oils.