Study On Pyrolysis Reaction Of Insulating Paper Based On Molecular Simulation

Cellulose insulation paper（cardboard）is the main component of the solid insulation part of the transformer.Since the transformer cannot replace the insulating paper,the aging of the insulating paper is closely related to the aging of the transformer.Oil-impregnated paper has good electrical and mechanical properties,which can not only extend the service life of the transformer,but also reduce the failure caused by the internal insulation problems of the transformer.Therefore,the study of the performance of the transformer’s solid insulation material is conducive to the safe operation of the entire power grid and improves its economic benefits.First,this paper uses molecular dynamics simulation of Reax FF force field combined with Monte Carlo method to analyze the pyrolysis process of transformer insulation paper from the perspective of microscopic atoms.Since molecular dynamics cannot describe the motion of atoms continuously,it can only describe the motion of atoms in a certain time step,so it is necessary to optimize the time step.In the molecular dynamics simulation experiment,we set up 10 different step variables to establish the model,analyze the bond formation and bond breakage of the product and conduct backstepping to obtain the optimal model of the transformer insulation paper pyrolysis reaction.And in the optimized model,deeply study the pyrolysis mechanism of the faulty insulation paper inside the transformer,the regularity of the products and the analysis of the broken and bonded conditions.The mass fraction of formic acid molecule.Secondly,this paper conducts a laboratory-prepared thermal aging experiment for oil-paper insulation,pre-treating the oil-paper insulation samples into vacuum oil-immersion tanks for drying,and oil-impregnated insulation paper with a ratio of oil-paper 10:1.Accelerated heat aging experiment was conducted on the processed samples in the aging box.During the aging process,the DP and water mass fractions of the insulating paper are measured.At a temperature of 130,use a viscometer to track the DP value of 45-day insulation paper aging,and use a Karl Fischer moisture meter to measure the moisture content of insulation paper in an oil-paper mixed system with an initial moisture content of 4.54%.In order to verify the percentage of moisture content of the insulation paper measured by the laboratory,this article sets up the molecular dynamics simulation of the pyrolysis of the insulation paper of the transformer at six different temperatures on the principle of obtaining the optimal step size,and calculates the H₂O molecules at different temperatures.The mass fraction of the paper is compared with the percentage of the moisture content of the insulation paper obtained from the thermal aging experiment of the oil-paper insulation prepared in the laboratory.The percentage of water content is the same as the mass fraction of H₂O molecule calculated in the molecular simulation experiment within the allowable range of error.The results show that the molecular simulation method used in this paper to simulate the pyrolysis reaction of transformer insulation paper is a supplement and verification to the laboratory method to study the aging experiment of transformer insulation paper.The molecular simulation experiment to simulate the pyrolysis of transformer insulation paper is also a method to study transformer insulation paper from a micro level.This paper optimizes its method and makes in-depth research on the microscopic mechanism to contribute to the continuous development of transformer insulation paper.