Electrical discharges influence on the dielectric properties of natural insulating oil

The aim of this work is to characterize a natural ester insulating liquid based on measurements of the dielectric parameters versus frequency (Frequency Domain Spectroscopy). The tests were carried out on a non-inhibited olive oil having high water content and submitted to electrical discharges (from 100 to 1600 discharges). The results so obtained show a significant increase of the dielectric constant and a decrease of conductivity when the frequency is increased.