Corona discharge as affected by the presence of various dielectric materials on the surface of a grounded electrode

International audienceThis paper is aimed at the characterization of the corona discharge generated from a high-voltage wire electrode facing a grounded plate that carries dielectric layers composed of granules, sheets, and non-woven media. Current-voltage and current-frequency characteristics were measured, respectively in DC and AC modes, for several values of the thickness of the PE granular layer, PET sheets and PP non-woven media considered in the present study. The measurements show that the corona onset voltage and the behavior of the current-voltage characteristics are dependent on both nature and thickness of the dielectric layer. Both the estimated capacitive component and the ionic component in AC mode vary with the amplitude and the frequency of the voltage. The ionic component is particularly affected by material non-uniformity