Negative Corona Characteristics on RTV SIR Coated Glass Insulating Surface under Ramp High Voltages

Corona discharges along pure and room temperature vulcanized silicone rubber (RTV SIR) coated glass insulating surfaces, are experimentally investigated in a non- uniform electric field electrode arrangement under negative ramp high voltages. The insulating surfaces were bridging a short needle-plane gap which was stressed by applying voltages just sufficient for corona inception up to values causing flashover; the case of air alone was considered as reference. The salient corona discharge characteristics, namely inception voltage and current as well as the energy dissipated were obtained. Results are discussed based on different modes of corona growth as affected by applied voltage and presence of an insulating surface. Corona growth along an insulating surface is suppressed, thus flashover occurs at a higher applied voltage.