Investigation of temperature effect on an epoxy resin: Aging due to partial discharges

This paper deals with the study of PD ageing in a flat cavity at different thermal conditions. Actually, we deem that mastering the aging of insulating materials under their real working conditions is of great importance for a good dimensioning of the insulating parts of power electrical equipment, such as components for cables, electrical machines and so on. Therefore, in this research the temperature is considered as an indirect aging factors, e.g. it concurs to the aging only affecting the PD activity. The material involved in these studies was an epoxy resin, supplied by Bakelite Kunstoffe Gmbh that has a wide range of application in HV insulation systems for impregnation purposes. Lifetime tests have been performed on samples with a flat cavity subjected to a 30 kV, 50 Hz sinusoidal voltage, at 30°C, 55°C and 80°C. It has been inferred that temperature strongly changes the PD activity during the ageing, affecting in an surprising way the materials lifetime. Complete accordance has been found in the physical and statistical analysis performed. Finally, Weibull α and β parameters are presented as good PD ageing indicators