Ageing of impregnated polypropylene film for capacitor application under combined electrical and thermal stress

In order to establish the service reliability of PP (polypropylene) film with new capacitor impregnants, life evaluation studies were conducted on scaled-down models of impregnated capacitor elements. The results of aging studies conducted under accelerated electrical and thermal stresses are discussed. The effect of combined stress aging on the electrical, mechanical, and chemical properties of the PP film has also been examined. It is shown that the use of the Eyring model appears appropriate for estimation of capacitor dielectric under multifactor stress. The effect of temperature on this dielectric system beyond 80°C is predominant