High-temperature dry-type transformer economics

THE ADVENT OF high-temperature insulations, such as silicones, has moved upward the possible design limit due to deterioration of insulation with temperature. Formerly, the transformer designer used insulation to the temperature limit dictated by its aging characteristics and a reasonable life. The point is now reached, however, at which other factors should be considered. Higher temperatures may cause large variations of electrical characteristics as the load is varied and also cost of losses may overbalance savings in initial cost, and the decrease in size and weight.