Influence of impulse breakdown delay of soil on lightning protection characteristics of transmission line

The impulse breakdown characteristic of soil is significant for evaluating the lightning trip-out rate of transmission lines. Firstly, this paper examined the impulse breakdown delay characteristics of soil through considerable experiments. Then the influence of the impulse breakdown delay phenomenon of soil on the lightning protection characteristics of transmission lines with different rated voltages is analyzed through the numerical calculation. Based on the results, the lightning electromagnetic transient process of transmission line considering the impulse breakdown delay was discussed. The analysis results indicate that the lightning withstand level has a decreasing trend with the increase of the soil impulse breakdown delay. The influence of the impulse breakdown delay on the lightning protection characteristics of transmission lines become weaker as the rated voltage level of transmission line increases.

► Impulse breakdown delay characteristics of soil obtained from considerable experiments.
► Impulse breakdown delay of soil influences lightning protection characteristics of transmission lines.
► Lightning electromagnetic transient process of transmission line considering the impulse breakdown delay.
► Lightning withstand level decreases with soil impulse breakdown delay increasing.