Lifetime evaluation of medium and small size power transformers part 1: Theory

A new methodology that combines analytical and experimental methods is proposed for evaluating transformer lifetime. This first part of a two part series focuses on aging and lifetime evaluation of oil sealed transformers. The second part focuses on an experimental study of the various elements of transformers. A new computational formula based on the degree of polymerization of (DP) of the insulation paper is proposed for lifetime evaluation of transformers.