Molecular dynamics simulation on the impact of electric field on the yield behavior of insulation paper

Oil-immersed paper, which has been universally utilized as insulation in power transformers, plays an important role in determining the lifespan of transformers. In the long-term operation of power transformer, oil-immersed paper will be subjected to electric stresses, the accumulation of the mechanical stresses and polarization of the electric field may cause deterioration to the insulation paper. For a long time, the effect of electric field on the insulation paper is mostly based on macro test, and the microscopic mechanism needs for further exploration. Therefore, in this paper, single chain and multi-chain cellulose models were built to study the yield behavior of cellulose under strong electric field by molecular dynamics simulation. Results indicated that: when applied strong electric field, yield behavior will occur on both of the single and multi cellulose chains. The single chain cellulose occurred irregularly yield behavior, just as the shape “V” and both ends of the cellulose chain orientated the same as the direction of the electric field while the central occurred opposite; the direction of multi chain cellulose was consistent with the electric field. The stress caused by electric field resulted in the yield behavior of cellulose, and eventually lead to the breakage of the cellulose chains.