Aging Diagnosis Method of the Mineral Oil Filled Transformers using Thermally Upgraded Kraft Paper by Furans in Oil

In recent years, the number of transformers using Thermally Upgraded Kraft paper (TUK) for winding paper has been increasing prevalent. In connection with this, the development of a new test method for aging diagnosing transformer winding using TUK is desired. The present study investigates the impact of the decrease in average degree of polymerization (DP) due to thermal deterioration of TUK on changes the furans generated. The test results shows that the total amount of furans generated was found to correlate with DP, and furans were identified as a potential aging marker for TUK deterioration. In addition, the production ratio of furans suggests the feasibility of estimating the state of deterioration.