A Theoretical Study of the Effects of Temperature Variation on Activation Energy in Oil- Paper Insulated Transformer

Oil-impregnated organic paper insulation in transformers invariably ages with time during its operation. Presence of moisture and operating stresses accelerate the insulation ageing process. Existing literature suggests that activation energy of the solid insulation has direct correlation with its conductivity value and operating temperature. Activation energy can be one crucial parameter in finding out the useful remaining life of transformer insulation. Condition based monitoring (CBM) has gained immense importance in recent years to avoid path to catastrophic failures. Laboratory experiments on oil-paper insulation system based on time-domain spectroscopy are performed in the present work. To study the influence of operating temperature on activation energy, insulation samples have been subjected to different degrees of heating. Ageing parameters, namely moisture content, tensile strength, and degree of polymerization, have been calculated. Finally, remaining life of the insulation sample has been estimated.