Properties of corona discharge under positive DC voltage at low atmospheric pressure

Using a ultra-violet camera, CoroCAM IV+, and a specially-designed pulse current sensor, the corona discharge at the tip-of-an-icicle/iced-plate electrode system was studied under DC+ and at low atmospheric pressure. The effects of the atmospheric pressure on the corona inception voltage, corona discharge type, discharge current waveforms and charge quantity were investigated. Based on the experimental results, some empirical equations were proposed for calculating the corona inception voltage. The results will advance our knowledge of corona discharges at icicle tips and help us to calculate the electric field distribution along ice-covered insulators more precisely.