Positive Wire-to-Plane Coronas as Influenced by Atmospheric Humidity

A method is suggested for calculating the inception voltage and corona current in humid air. It is found that the photoelectrons distribution within the ionization layer, which depends upon the gap geometry, plays an important role in deciding whether the inception voltage increases or decreases with relative humidity. The inception voltage is one of the boundary conditions required in the theoretical analysis of the corona V-I characteristics also presented. The experimental results reported in the literature which differ widely can be explained in the light of the present findings.