A Simplified Physical Model of Upward Connecting Negative Leader for the Design of LPS Against Positive Lightning

Although positive lightning strikes are less frequent, they are more destructive than negative ones. A simplified physical model of upward connecting negative leader (UCNL) in long spark is proposed in this paper. In contrast with the upward connecting positive leader, the UCNL is always stepped, which is reproduced in our model. The model was verified using experimental data for negative sparks in a 10-m rod-plane air gap. The model can be used to analyze the attachment process of positive cloud-to-ground lightning strikes to grounded structures and serve to improve the design of lightning protection systems.