Impact of an DC electric field on the charge accumulation at the pressboard/oil interface

Mineral oils are commonly used for cooling and electrical insulation purposes in electrical power transformers and other electrical apparatus. Flow electrification of insulating liquids in different ducts has been studied for a long time. The physicochemical process appearing at the solid/liquid interface creates the electrical double layer. To study this phenomenon, a facility was designed a few years ago. It consists of a closed circulation loop where oil flows through a rectangular channel and allows measuring a streaming current and the accumulated charge on the pressboard during the flow. The present work focuses on the influence of external DC electric field.