Study of the contamination thicknesses effects on DC corona streamer pulses based on a corona cage

The previous research work has dealt with corona characteristics of conductors coated with different types of contaminations, while the thickness is rarely considered. To fully study the effects of conductor surface condition on photon count and corona streamer pulses, conductors coated with different thicknesses of contamination are investigated and compared with a clean one. An experimental system based on an indoor corona cage was established to exclude the interference from environmental factors. In the experiment, kaolin was used as the coating contamination on the surface of the conductors. Experimental results illustrated by both ultraviolet photographs and measurement data reveal that the effects of contamination thicknesses on corona characteristics and current pulses are obvious. It can be inferred that the dielectric coating resists corona discharge and enhances the onset voltage when the contamination is uniform enough.