Static Electrification in Aged Transformer Oil

We have examined the influence of thermal aging and partial discharges on the static electrification of transformer oil. The experiments have been carried out in a laminar flow region within the temperature range of 20 to 800C using flow pipes made of various materials. The thermal aging process causes evident quantitative as well as qualitative changes of the charge measured. Furthermore, it is found that partial discharge aging causes no essential changes in oil electrification. Nevertheless, some changes are observed for high-intensity partial discharges.