Dc breakdown voltage of carbon dioxide medium under needle to plane electrode

This paper reports the experimental results on the corona onset voltage and breakdown voltage by positive and negative dc discharges in carbon dioxide medium within the pressure range of 0.1 to 15MPa under the needle to plane electrode. From the experimental results of dc discharge, negative corona discharges are observed more clearly in liquid and supercritical phase than in gas phase of carbon dioxide. However, in our experimental condition, positive corona discharge was not found for dc discharges. The breakdown mechanism in liquid can be classified into two categories on account of the bubble-triggered formation.