Research on the Influence of Moisture Exchange between Oil and Cellulose on the Electrical Parameters of the Insulating Oil in Power Transformers

The article presents an oil moistening method, identical to the in power transformers. Moistening took place through migration of moisture from moistened pressboard brand new oil. AC electrical parameters (admittance, phase shift angle, permittivity, loss tangent and conductivity) insulating were tested. All measured found be affected by moistening. greatest changes observed conductivity. Moisturization increases value tanδ at a frequency 10−4 Hz about 20 70. With increase 400–1000 Hz, minimum is observed, position which depends on temperature. Its for six times lower than This moisturizing increased activation energy conductivity 0.466 ± 0.0265 eV 0.890 0.0115 eV. likely due acceleration water molecules diffusion into with increasing temperatures. caused should taken account while analyzing transformers insulation condition using FDS method.