Electric Characteristics of Dry-type Polyester Film Insulation with Different Thermal Aging States

The dry-type air-core reactor is composed of several coils insulated by polyester film with good insulation capability and enclosed by epoxy resin impregnated with long glass fiber. The dry-type air-core reactor accidents show that turn-to-turn insulation failure is the most common one occurred during operation of air-core reactor. Such failure often leads to short circuit of turn-to-turn insulation and further burns the reactor. The extensive researches on thermal aging analysis mainly focus on oil-impregnated paper in past decades, but barely dry-type insulation materials. The objective of our thermal aging experiment is to develop a correlation between thermal aging and electrical as well as mechanical characteristics of polyester film. All these are done through an accelerated thermal…