Evaluation of the Aging of Oil-Paper Insulation Using an Improved Fractional Poynting-Thomson Model

Assessment of the aging of oil-paper insulation is analyzed in this article, based on an improved fractional Poynting-Thomson model, which includes dc and hopping conductivity (P-T model(2)). Based on samples of oil paper produced in laboratories with different thermal aging times, it has been found that the proposed improved model provides a better fit and a higher index of coincidence concerning the measured values than the traditional P-T model and the model that only incorporates the effect of dc conductivity (P-T model(1)). Nevertheless, comparing the proposed improved P-T model with the traditional Cole-Cole (C-C), Davidson-Cole (D-C), and Havriliak-Negami (H-N) models, the improved P-T model(2 )also demonstrated a superior fit for the measured value and a higher coincidence index than another model. In addition, there was an excellent exponential relationship between the quantities epsilon(a), epsilon(b) and tau of the improved model and the furfural content of the samples. Consequently, these characteristic quantities could be utilized to estimate the furfural content in the oil-paper insulation and evaluate the insulation's condition.