Application and evaluation of transformer insulating materials

Transformer insulation is a broad subject involving many types of materials and numerous methods of test. These materials can be combined in many ways in different designs to operate under various environmental conditions. In addition, insulating materials are called upon to help meet the thermal and mechanical requirements of a transformer as well as the dielectric requirements. This paper is general ill scope in dealing with the manufacturer´s point of view in the field of insulation for power and distribution transformers. Progress is traced and the problems of the transformer designer are discussed from the standpoint of suggested developments in the application and evaluation of new and improved insulating materials.