Advances and problems in the maintenance of liquid insulation

The importance of several problems has been emphasized by advances recently made in the thinking and operating techniques concerned with the maintenance of insulating liquids such as transformer oil. These advances are the direct result of a program of directed research conducted by a large group of power systems cooperating through a clearing-house laboratory and the are based upon the new concept that insulating oils when properly serviced can be given unlimited extension of life free from the formation of sludge or excessive acidity due to oxidation, even in free-breathing transformers.