A life model for epoxy resins subjected to PD activity at different temperatures

The preliminary stage activities of a medium term research program aimed at studying the aging process of electrical components due to partial discharges (PD) and temperature are illustrated. In this aim, the Cigre' II test assembly was used to study epoxy resins performance under real working conditions, e.g., under the simultaneously action of PD and temperature. Collecting these data with the previously ones obtained in different test cell configurations, an analysis of direct and undirect multistress action on the epoxy material has been developed on the basis of what said by the International Electrotechnical Commission in IEC-792-1 publication, 1985. In this contest a simple phenomenological life model is proposed, based on a suitable choice of the stress function, e.g. that takes into account of voltage and temperature. The latter represents an useful background for the real working conditions of materials.