The determination of charge behavior at a liquid-solid interface

A methodology has been developed to provide information on the way in which charges distribute and relax on cellulose surfaces and on their impact on the breakdown of oil-cellulose insulation. Using this approach, not only can the charge be monitored in time, but its spatial distribution can be ascertained. The method has further been extended to apply an interrogating impulse voltage across a charged surface which permits the impact of surface charge on creep breakdown to be determined. Field plots which allow the calculation of a power frequency (capacitive) distribution in the presence of a static charge reveal that the impact of accumulated surface charge on the dielectric integrity of transformer structures is significant and should be considered in design criteria