High temperature and ageing test methods to characterize the dielectric properties of BOPP capacitor films

A large-area high temperature breakdown measurement and an ageing test method are presented. These methods facilitate the development of reliable higher energy density film capacitors by exploiting large measurement areas to provide information on weak point formation and subtle changes in breakdown behavior after electro-thermal or thermal ageing. The test methods were used to characterize two types of highly isotactic biaxially oriented polypropylene capacitor films, which had similar breakdown behavior at room temperature, but different breakdown properties at high temperature and out of which one was more susceptible to electro-thermal DC ageing.