The Effect of Corona Discharge on Leader Initiation in Long Air Gaps

In this paper, the effect of the corona space charge on the leader initiation is experimentally and theoretically investigated. The critical corona charge for the stem-leader transition is reviewed and a more proper charge criterion is recommended based on the experimental measurements and theoretical analysis. It is shown that the chocking effect of the corona space charge for the second corona inception should not be ignored, which decreases the electric field strength of the stem tip and hinders the initiation of the leader. A simple physical model is proposed to calculate the leader initiation time, which can consider the thermodynamic mechanism for stem-leader transition and the chocking effect of the corona space charge, and a good agreement with the experimental results was obtained.