Experimental Study on Corona Characteristics of Ball-Plate Electrode under High Humidity

In order to deeply study the corona problem of power fittings in high-humidity areas, an artificial humidity climate chamber was designed to conduct corona experiments on the ball-plate electrode under high humidity. During the experiments, the photon number of the ball electrode with different humidity and voltage was recorded by the ultraviolet imager. The corona initiation voltage experiments at relative humidity of 50%, 60%, 70%, 80%, 90% and 97% are conducted respectively. Under the high humidity condition of 97% with the condensing state, the corona initiation voltage experiment also was taken to compare with non-condensing state. Finally, the influence of each stage of the dewdrop development process on the electric field is analyzed through electric field simulation. The experimental results show that as the humidity gradually increases from 50% to 97%, the ball electrode’s corona initiation voltage drops from 97.5kV to 48kV decreasing of 50.7%. When the humidity is 97%, the corona initiation voltage of the ball electrode with condensation is 29.6% lower than that without condensation. Under the same voltage, the number of photons at the moment of the dew drop is the largest. In the electric field simulation analysis, as the accumulation degree of the dew drop increases, the distortion of the electric field increases, the electric field distortion is the most serious when the dew drops is consistent with the maximum number of photons in the experiment.