Investigation of Interaction between Polymer Film and Insulating Oil by Dielectric Property Measurement

Interaction between polymer film and insulating oil, which is proposed for use in the insulation of ultra high voltage power cables, is investigated by dielectric property measurements. For the investigation, variations of dielectric constant, dissipation factor, and mean thickness of polymer films caused by oil impregnation are measured by a newly developed high-resolution dielectric property measuring system based on a unique method. The investigation has shown that the influence of oil absorption appears much larger on dielectric properties at around 100 MHz than on those at lower frequencies, and has proved that this method is effective for such a purpose.