INFLUENCE OF MOISTURE CONTENT ON ELECTRICAL AGING LIFETIME OF VEGETABLE OIL-PAPER INSULATION

Vegetable insulating oils are fire-resistant and environmental-friendly liquid dielectrics, which offer excellent electrical and physiochemical properties and have been successfully used in distribution transformers. The huge differences in molecular structure between vegetable oil and mineral oil make vegetable oil hydrophilic compared with mineral oil, so it is very necessary for evaluating the influence of moisture content on the lifetime of vegetable oil-paper model. In this paper, electrical aging tests of vegetable oil-paper insulation with different moisture content were conducted, and the relationship between the voltage endurance coefficient and moisture content in paper was also obtained and compared with those of mineral oil-paper insulation. The results show that the electrical…