Aging Mechanisms of Transformer Oils and Their Aging Markers

Transformer oils (TO) are used for filling power and instrument transformers, reactor equipment, and oil switches. During the operation of a transformer, profound changes occur in the transformer oil, which are usually called aging. The article discusses the features of the luminescence spectra of transformer oils of different brands (GK, T -1500, TKp), oils with different dielectric loss tangents and acid numbers (AN) (with different degrees of aging). The purpose of the study is to develop new markers of aging of transformer oil, using changes in the composition of aromatic compounds in it and associated changes in the luminescence spectra of these oils. Based on the analysis of literature data and conducted research, the dependence of the luminescence spectra of oils on the brand of oils has been established; it has been shown that in the series of oils GK, T -1500, TKp, the concentration of complex aromatic compounds increases, which leads to a shift in the luminescence spectra of oils towards longer wavelengths. During the aging process of oils, the concentration of aromatic compounds also increases and their structure of molecules of aromatic compounds changes, the intensity of luminescence of transformer oil increases, as well as a shift in the luminescence spectra of oils to the red region of the spectrum. Aromatic compounds as a marker based on luminescence spectra make it possible to determine the brand of transformer oil, the degree of aging of oils, and can also be used in the regeneration of oils to determine the degree of aging.