Diffusion Motion Analysis of gas Molecules in Oil - paper Insulation System Based on Molecular Dynamics Simulation

The diffusion movement of small gas molecules in oil-paper insulation has an important influence on the insulation state evaluation. In order to reveal the diffusion mechanism of small molecules in oil-paper insulation system from the microscopic level, the diffusion behavior of small molecules in common H2O, CO2 and C2H4 gases was simulated by molecular dynamics. Molecular simulation software was used to build the model of insulating paper and insulating oil, and two kinds of small molecule diffusion models were built on this basis. The difference of diffusion characteristics of gas small molecules in oil-paper medium was discussed, and the distribution influence and diffusion mechanism of gas small molecules in insulating oilpaper were obtained. Studies have shown that the diffusion coefficient of gas small molecules in cellulose is one order of magnitude smaller than that in insulating oil, and the order of diffusion coefficients of three gas small molecules in two media is also different. Water molecules are especially easy to do diffusion movement in insulating oil. When encountering insulating paper, the movement will be hindered, and the macroscopic performance is the water absorption characteristics of insulating paper.