In order to see the transformer insulation status, the temperature profile, the degree of polymerization (DP), the furan compound content, the carbon dioxide, and carbon monoxide concentration are monitored. By evaluating the degree of polymerization (DP) of the cellulose paper insulation and furans in the determination of the insulating oil, it can estimate the lifetime of the transformer. Analysis of cellulose insulation paper to see the degree of polymerization (DP) can be performed safely only when the transformer is interrupted. However, being a non-invasive test, determination of furane content in an oil-insulating oil is often used as an alternative method for measuring the DP average of insulation paper. In order to analyze the technical condition of a transformer, furan content in oil should be used and interpreted as a primary chemical indicator in conjunction with the results of carbon oxide from the dissolved gas analysis, the acidity and moisture results from the chemical tests, the methanol content from the chromatographic tests and other monitoring techniques.
The Effect of the Chemical Constitution of Insulating Oil on Dielectric Breakdown in the Oil-Impregnated Paper Insulation