Experimental investigation on humidity effects on the variations of positive DC corona discharge

In order to study the effect of humidity on the variations of positive DC corona discharge, an artificial climate chamber was developed to perform corona experiments. Based on the testing system, the photon counting rate, the total electric field strength and the ion current density on the ground level were measured by the UV imaging detector, the rotating DC electric field mill and the Wilson plate respectively. The relatively humidity during the experiments was kept within the range 40% to 90%. Moreover, the relationship between the calibration coefficient of the field mill and relatively humidity was also investigated. Experimental results showed that the photon counting rate and the total electric field increased with the raise of relative humidity, while the ion current density and the calibration coefficient decreased with the raise of relative humidity.