An assessment on aging model of IEEE/IEC standards for natural and mineral oil-immersed transformer

This paper presents an assessment on aging model of IEEE and IEC standards using thermal model of oil-immersed power transformer for natural ester and mineral oil. For this purpose, a model created for the analysis of behavior transient thermal performance with aging both of natural ester and mineral oils. Thermal model of the transformer is based on thermal-electrical analogy that is calculated separately for natural and mineral oils covering top-oil and hot-spot temperatures. The hot-spot temperature values of each ester/oil are used to calculate aging parameters which include the aging acceleration factor, time dependent relative aging rate and insulation life loss variations.