Evaluating the influence of moisture on the dielectric response of insulating organic composites

Organic additives may improve the electrical properties of epoxy resin. Another issue is the deterioration of the electrical performance of epoxy resin due to moisture, which may diffuse into the insulation, e.g. of HV devices, under certain conditions. The aim of this work is to investigate, with dielectric spectroscopy, if there is an effect on the latter issue. By considering two specific example additives, we find that at one of them leads to an enhancement of the moisture-induced dielectric losses at elevated temperatures. We thus conclude that in general, an improvement of epoxy resin insulation material by organic additives should not consider only dry epoxy, but always consider if there are changes in the electrical properties under exposure to moisture.