Change of Loss Factor On the Surface of Transformer Paper Due to Thermal Degradation

This publication deals with changes in the loss factor on the surface of the impregnated transformer paper in the event of thermal degradation. The theoretical part discusses the properties of insulating materials used in the chosen experiment and a description of the impedance spectroscopy method in the frequency domain. The practical part contains experimental description, used transformer paper samples impregnated with different types of transformer oil and analysis of measured results with dependencies of loss factor, depending on frequency.