Effect of Thermal Aging on the Properties of Insulating Paper

In order to improve the safety of power equipment, the influence of thermal aging on the performance of insulating paper used for transformers was investigated, the same type insulation paper with different basis weight was used to simulate the thermal aging process. The paper folding endurance, the tensile strength and the fiber polymerization degree (DP) of the insulation paper were measured before and after the thermal aging. The result showed that thermal aging has deteriorated the paper's properties, the DP was decreased. The retention rate of the paper folding endurance was about 10% of the base paper, and the retention rate of the tensile strength was about 70% of the base paper. Compared to the tensile strength, the connection between the fibers has a greater impact on the paper folding endurance of the insulating paper. Therefore, paper folding endurance was a more realistic and efficient method to characterize the thermal aging degree of the insulating paper.