The Impact of Moisture Diffusion From Paper-Oil Insulation on Oil DC Conductivity

The paper presents a study of the polarization current of brand-new mineral oil and moistened oil by diffusion from moistened paper-oil insulation with a moisture content of (5 ± 0.2) % by weight. The oil moistening method used in the study enabled the maximal reproduction of phenomena occurring in transformers. Based on the obtained measurement results, the temperature dependencies of the DC conductivity and the activation energy values of the conductivity of the brand-new and moistened oil by diffusion were determined. The obtained measurement results indicate a change in the activation energy of conductivity due to the moistening of the oil, which may significantly affect the accuracy of determining the moisture content of transformer insulation