Multiple Sulfur Corrosion Simulation on the Oil–Paper Insulation System Under Synergistic Electric and Thermal Fields

Sulfur corrosion in transformers results in insulation deterioration failures. Therefore, in this study, multiple sulfur corrosion was simulated on the oil–paper insulation system. The mechanical properties and hydrogen bond of the insulating paper as well as the mean square displacement (MSD) and shear viscosity of the insulating oil were investigated under different combinations of electric and thermal fields. The electric field could promote the degradation of the elastic modulus of cellulose. The influence of the ac electric field on the modulus is not as obvious as that of the dc electric field. The temperature has a significant effect on the modulus parameters. With the increase in temperature, the elastic modulus decreases considerably. The radial distribution function (RDF) of the model was also investigated. Cellulose can easily form intramolecular hydrogen bonds under ac electric fields. Furthermore, intermolecular hydrogen bonds are easily formed under a dc electric field. The shear viscosity of insulating oil decreases with the increase in temperature. The presence of the electric field could increase shear viscosity. The results of the study can provide some reference for the microscopic mechanism of multiple corrosive sulfides and investigate effective protection techniques against sulfur corrosion.