Influence of DC electric field on charge accumulation by flow electrification in pressboard power transformers

Mineral oils are commonly used for cooling and electrical insulation purposes in many electrical power apparatus. In power transformers, the forced oil flow on the pressboard surface is suspected to be responsible of breakdowns. Due to flow electrification phenomena and the electrical double layer, the accumulated electrical charge may lead to increase the local electric potential highly enough to induce electrostatic discharges. The aim of this work is to study the impact of a DC electric field on the accumulated charge within the pressboard.