Compared with mineral oil, vegetable oil has the advantages of high ignition point, high flash point, renewable and easy to degrade, which also plays a better role in the protection of insulating paper. At present, the microscopic mechanism of thermal decomposition of insulating paper is still unclear, and the microscopic influence law of mineral oil and vegetable oil on insulating paper has not been proved. In this paper, models of insulating paper with different types of insulating oils are established and molecular dynamics simulations based on the reactive force field (ReaxFF) are performed. The reaction paths and characteristic products of the degradation process of insulating paper are obtained and statistical analysis of the bond breaking probability of pyran rings in insulating paper is carried out. It is found that the first step in the cleavage of insulating paper was the cleavage of the glycosidic bond, followed by the opening of the pyran ring and the cleavage of the hydroxyl group. In addition, the degradation of insulating paper in mineral oil is more severe than that in vegetable oil. The above research revealed the microscopic mechanism of the cracking process of insulating paper, and proposed the influence rule of mineral oil and vegetable oil on insulating paper. This work can provide theoretical basis and technical support for further exploration of the effective degradation protection technology of transformer oil-paper insulation.

vegetable oil,mineral oil,insulating paper,ReaxFF,molecular dynamics