Main power transformers for generating stations

TODAY many factors, including cooling, rating, and number of phases, affect the selection of the main power transformer. The types of transformer cooling now available are: type OA, self-cooled; type OW, water-cooled; type OA/FA, self-cooled/forced-air-cooled; type OA/FA/FA, self-cooled/forced-air-cooled; type FOA, forced-oil-air-cooled; and type FOW, forced-oil-water-cooled. The choice of the method of cooling for a transformer may depend on consideration of load cycle requirements, first cost, losses, reactance, installation cost, maintenance cost, shipping limitation, and other factors.