The Influence of a Solid/Liquid Interface on Electric Conduction Characteristics under Non-uniform field in Transformer Oil

Abstract

It is shown in this paper that the electric conduction in transformer oil is significantly affected by the presence of a solid/liquid interface. Using a blade-plane electrode geometry, we investigated the influence of an insulator inserted along the plane of symmetry of an electrode gap on conduction currents in transformer oil. Though the stationary relationship between current I and voltage V always showed the linear plots of V vs. I^1/3, conduction currents were prominently decreased by the presence of the insulator. This reduction of current is discussed on the bases of the electrohydrodynamic (EHD) motion and the electric field of the blade edge taking the insulator surface charging into account.