Static electrification assessment of transformer oils in the spinning disc system

The present paper is devoted to the study of the Electrostatic Charging Tendency (ECT) of fresh (unused) and aged transformer oils using a spinning disk system. A series of experiments were conducted under laboratory controlled conditions. The monitored parameters (conductivity, dissipation factor, water content, dissolved decay products, resistivity, turbidity ...) show that the electrification currents increase with temperature, fluid motion velocity, surface properties and the aging byproducts of the oil. The polarity, the amplitude and the time constant of the electrification currents are also affected. This contribution is not only intended to provide a fresh review in this domain of research, but also contains a substantial amount of new material with a view of closing some gaps in the present state of knowledge of oil streaming electrification.