A great many transformers, including all the large ones and all the high voltage ones are immersed in mineral oil which serves the double purpose of cooling and insulating the windings.

• 大量的变压器,包括所有的大型变压器和所有高压变压器是浸于矿物油中的,矿物油起冷却和将绕组绝缘的双重作用。