Models for life prediction in surface PD on polymer films

This paper studies the behavior of different thin polymeric films subjected to surface partial discharges. Particularly the time degradation of the film, in different test conditions, is analyzed with special attention to relative humidity conditions. The aim of this work is to identify the characteristic quantities related to the above described kind of aging. In this way it will be possible to define one or more experimental models that can lead to identify the degradation level of the material and then to estimate its life time. The characteristic quantities are obtained through elaboration of the apparent charge that is measured and acquired by means of a digital measurement system; they are identified as 'external power' and 'apparent current'. Five different models to predict the life time are here defined using the inverse power law and the relevant results are analyzed and discussed.