Insulation with oil-impregnated insulating paper is the main form of insulation in transformers. This kind of insulating paper is commonly known as "kraft paper" and forms a paper-oil-paper insulation system after being immersed in oil. China has successfully developed 500kV, 750kV transformer turn-to-turn insulation paper, but it has not broken through the technical problems for 1000kV transformer. These technical problems include: chemical purification, structural design and shaping of the raw material of insulating paper. We need to have a deeper understanding of the relationship between the performance of oil-impregnated insulating paper and the preparation technology to optimize the production process.
