Molecular Simulation Study On The Influence Of Nano-TiO₂ Doping On The Microscopic Properties Of Insulating Paper

As the core equipment of power system,transformer’s internal insulation system is composed of oil-paper.With a large number of UHV transmission lines in China’s 13th five-year power plan,transformer insulation is facing higher insulation requirements,and traditional insulation system is difficult to meet the requirements of contemporary transmission lines.In the process of transformer operation,the insulation oil of inner insulation can be replaced to meet its insulation requirements,while the insulation paper cannot be replaced due to deterioration.Therefore,improving the performance of insulating paper cellulose is a key link to enhance the performance of inner insulation.As nanoparticles doped modified insulating paper become a research hotspot,Nano-TiO₂ by the doping of insulating material application,but only use the macro experiment study,the lack of the microscopic characteristics of Nano-TiO₂ doped insulating paper,so the use of molecular simulation to study the microscopic characteristics of Nano-TiO₂doped insulating paper has certain academic value and practical significance.This paper will study the microscopic mechanism of Nano-TiO₂ doped insulating paper cellulose.Firstly,considering the study on the electric field of Nano-TiO₂ doped oil-impregnated insulating paper in the macroscopic experiment,the effect of Nano-TiO₂ doped oil-impregnated insulating paper cellulose on the electric field intensity was studied by using quantum mechanics to supplement the microscopic characteristics of Nano-TiO₂ doped oil-impregnated insulating paper.Then,molecular dynamics was used to study the amorphous model of pure cellulose and Nano-TiO₂ doped cellulose with different particle sizes,and the optimal doping particle size to improve the mechanical strength and thermal stability of cellulose was explored from the aspects of mechanical strength and thermal stability.Finally,molecular dynamics was used to study the effects of different Nano-TiO₂ doping contents on the mechanical strength and thermal stability of cellulose,and explore the nano contents with relatively good doping effect.The main conclusions of this research are as follows:（1）According to the research of quantum mechanics,the inflection points of the electric field intensity of the HOMO energy level difference,total energy difference and energy gap of oil-immersed（C-Y）and oil-immersed Nano-TiO₂ doped insulating paper（C-Y-TiO₂）were all greater than C-Y.Therefore,Therefore,microscopic studies have proved that Nano-TiO₂ doping makes the breakdown field strength of oil-impregnated insulating paper increase relatively.（2）The mechanical strength and thermal stability of Nano-TiO₂ doped cellulose were improved;As the doping size of Nano-TiO₂ decreases,the mechanical strength and thermal stability of cellulose are relatively better,so the doping size of small Nano-TiO₂ is an effective method to improve the mechanical strength and thermal stability of cellulose.（3）Different Nano-TiO₂ doping content has obvious content effect on the mechanical strength and thermal stability of cellulose.When the doping content of Nano-TiO₂ is about2.4%～2.8%,the mechanical strength of cellulose has a relatively good improvement effect.When the doping content of Nano-TiO₂ was between 3.2%and 3.6%,the thermal stability of cellulose had a relatively better effect.