Water distribution characteristics of synthetic ester oil-paper insulation interface under electro thermal action: A molecular dynamics simulation

Like a new kind of liquid insulation material for power transformer, synthetic ester has excellent electrical and insulation properties, but its research is still at the exploratory stage. Moisture distribution is the key factor for aging of grease insulation system, and it is difficult to observe through macroscopic experiments. The migration characteristics of H 2 O between insulation paper and synthetic ester were investigated from a microscopic perspective under the range of electric field from 0.0 V Å ⁻¹ to 1.0 V Å ⁻¹ and the temperature from 300 K to 360 K. The findings indicate that the diffusion of H 2 O will be limited as the electric field increases. The diffusion ability of H 2 O will be enhanced with temperature increasing, but due to the viscous force at the interface between synthetic ester oil and paper, H 2 O can only stay at the interface. The electrostatic interaction energy between cellulose and water increases with the electric field increasing. Therefore, the electrostatic interaction energy has a major contribution to the increase of the total interaction energy. On contrary, in the temperature range of 300 K to 360 K, there is a reduce in the energy of the interaction between H 2 O and cellulose molecules with the temperature rising.