The impact of composite AC-DC voltage on characteristics of corona discharge in rod-plane air gaps

In order to obtain the corona characteristics of electrodes under positive DC and AC composite voltages, the experiment platform of series circuit was established by using a stainless rod-plane electrode, in which rod electrode was applied with positive DC voltage, and plane electrode was applied with AC voltage. The change of ultraviolet photon counting was used as the corona criterion and the characteristics of corona inception voltages were studied. Besides, the influences of composite voltages and geometrical size on the electric field distribution were also investigated. It was found that, in the same atmospheric conditions and electrode arrangement, there exists the minimum corona inception voltage under a certain combination of AC and DC voltage. On the basis of the simulation results of electric field, the variation of composite electric field strength agrees well with that of corona inception voltage under composite voltages. The maximum electric field strength of electrodes decreases with the increase of rod radius or air gaps when fixing the composite voltages of AC and DC.