Fundamental studies on development of environment friendly new generation oil-filed transformer

摘要

Recently, need to consider social environment is increasing together with needs for improvement in economical efficiency and miniturization of an electric power apparatus. Generally, a high voltage-large capacity oil-filled transformer has adopted a composite insulation system which is composed of transformer oil and pressboards, from the point of view of electric strength and cooling. Occurrence of a creepage discharge on the surface of pressboards in insulating oil becomes an electrical weak point in such the insulation system. So in order to develop an oil-filled transformer which is friendly to environment, rape-seed ester oil which is vegetable oil is taken notice as new insulating oil. In the present paper, a propagation process of the creepage discharge in rape-seed ester oil is observed in detail, and results obtained are compared with ones obtained in transformer oil.