Operating Experience on AG&E 132-Kv System with Transformer Insulation Reduced Two Classes

This paper discusses briefly the historic background and reasoning behind the application of an insulation level reduced two steps in transformers used on the American Gas and Electric Company (AG&E) 132-kv system and the operating experience obtained on seven transformers banks using this insulation level. It also indicates advantages that may be obtained by using this low level of insulation.