Thermal Aging Characteristics of New Insulating Oil-Bamboo Paper Composite Material

Bamboo grows rapidly and can be continuously recycled, which is beneficial for environmental protection. What is more, bamboo exhibits good pulping performance second only to softwood and can to some extent replace the softwood pulp. However, currently, the insulating paper used in the electrical industry is mostly made of softwood pulp. In this article, the properties of transformer insulating oil-bamboo paper, which is used in oil-filled electrical equipment, were researched. The thermal aging characteristics of bamboo paper and softwood paper impregnated with insulating oil were compared. Based on the research results, it is found that the degree of polymerization (DP) of bamboo paper is obviously higher than that of softwood paper in the middle and late aging period despite the DP of new bamboo paper is lower than that of new softwood paper. The dissolved gas content and the acid value in the oil of the insulating oil-bamboo paper system are significantly lower than that of the insulating oil-softwood paper system throughout the aging process, which indicates the lower reactivity of the bamboo paper with transformer oil. The conductivity of the insulating oil-bamboo paper is relatively lower, and the breakdown strength is higher than that of the insulating oil-softwood paper in the middle and later stages of aging, which proves that the insulating oil-bamboo paper has better electrical performance during aging process. It is indicated that insulating oil-bamboo paper has more excellent structural stability and thermal aging resistance than traditional insulating oil-softwood paper.