Investigation on Diffusion Mechanisms of Methanol in Paper/Oil Insulation Based on Molecular Dynamics Simulation

Abstract

Methanol is regarded as an available indicator to analyze the aging condition of cellulose insulation. However, the diffusion mechanism of methanol molecules in the paper-oil insulation system is still unclear, since it cannot be explored by using only experiments. Given this issue, the molecular dynamics simulations were performed to investigate the diffusion mechanism of methanol molecules. In the current work, the mean square displacement of methanol during the diffusion process was calculated and analyzed, as well as its trajectory tracking. Then, the research on interaction energies and hydrogen bonds in paper/oil system were conducted. Finally, the effect of temperature on the diffusion of methanol molecules was also studied. Findings revealed that the diffusion of methanol in cellulose insulation is faster than that in insulating oil, besides, the presence of hydrogen bonds affects the diffusion rate of methanol molecules in cellulose insulation and insulating oil. Thus, the present findings could support the investigation of the diffusion mechanisms of methanol molecules, by which the aging condition evaluation of cellulose insulation could be also promoted.

An Experimental Analysis of Degradation of Cellulosic Insulating Material Immersed in Natural Ester Oil for Transformer

“…Wherever, cellulosic insulating material is impregnated with the MO, which enhances the insulation integrity as well as the life cycle of insulation medium. Solid insulating material is made upon the cellulosic insulating materials [3]. The kraft paper is used to provide insulation between the turn of transformer windings.…”

Dynamics of an impurity ion transport in oil‐paper insulation under various electric fields

“…In previous simulations of the diffusion behaviour of water molecules or gas molecules in mineral and vegetable oils, it has been demonstrated that the diffusion coefficients of those impurity molecules are generally higher in mineral oils than in vegetable oils, and their diffusion abilities are closely related to the molecular mass and polarity [25][26][27]. While in the insulating paper, the diffusion coefficients of impurity molecules are drastically reduced compared to those in transformer oil [28][29][30]. Moreover, according to the MD simulations conducted by Tang et al, the addition of nanoparticles, whether in cellulose paper or transformer oil, could significantly reduce the diffusion coefficients of impurity molecules in oil-paper insulation as the nanoparticle surface exhibits a strong attractive potential that limits the migration of impurity molecules [31][32][33].…”