Influence of coating of metallic surface on static electrification phenomena of transformer oils
Résumé
This paper is aimed at the study of the influence of the properties of the solid/oil interface as well as the temperature and fluid motion on the static electrification phenomena of transformer oils. The investigations are achieved on a spinning disk system in which the disk is either uncoated or coated on both sides with deposits of thin layers (0.5 and 2 μm) issued from three kinds of materials namely conducting (aluminium), semi-conducting (silicon) and insulating materials (polytetrafluoroethylene known as Teflon). It is shown that the modification of the surface properties has a deciding influence on the electrostatic charge tendency (ECT) of insulating oils ; the sign and the amplitude of the electrification currents are also affected.