Oil sulfur corrosion phenomenon existing in the transformer winding may cause the corrosion reaction of action sulfur and copper in insulation oil. When reaction products diffuse into the oil-paper insulation system

the the dielectric loss and the dropping of resistivity will increase

which is a factor causing the electric power equipment failure. Therefore

using the grain boundary engineering（GBE） technology

and optimizing the preparation technology of copper winding rolling shape in the process of variable parameters

we focused on controlling the microstructure of copper winding so as to improve its oil sulfur corrosion resistance as well as research the effect of the oil insulation properties after corrosion experiment. The results show that the treated copper（"GBE"-Cu） by GBE technology does not present corrosion phenomenon and the copper content in oil of "GBE"-Cu sample decreases from 3.66 mg/kg to 0.466 mg/kg. After corrosion experiment

the basic physical and electrical properties of the GBE-oil are superior to those in origin copper winding

which also contributes to decreasing the aging degree of insulating oil.