Molecular simulation of moisture diffusion in vegetable insulation oil at different temperatures

The existence of moisture has a greatly negative influence on the insulation properties of insulation oil. In this paper, the molecular dynamics simulation method was used to study the diffusion behavior of moisture in vegetable oil. The oil model with water-containing was constructed in the paper, and molecular dynamics simulations were performed at a temperature range of 343K to 423K. The simulation results show that when the temperature increases from 343K to 423K, the number of hydrogen bonds decreases by 44.23%, and the interaction energy increases from -82.826kJ/mol to -42.196kJ/mol. And the simulation results of moisture motion trajectories show that the increased temperature causes intensified moisture movements. This paper explains that vegetable oils have a stronger water soluble from a micro perspective.

I. Introduction

As the cooling and insulating materials of oil-immersed transformer, insulation oil plays a significant role in the operation of transformer. Mineral oil was widely used in transformers, but it has some disadvantage, including low flash point, poor biodegradability rate, and none-renewability. However, as a new environmental protection insulation medium, vegetable oil has¹ the characteristics of high flash point, complete biodegradation and environmental friendliness, which makes it a substitute for mineral oil^[1–5].