Investigation of Lightning Rod Shielding Angle

This paper studies those parameters affecting the shielding angle of the lightning rod (Franklin Rod) above very tall buildings. It is recommended that the shielding angle of the lightning rod is about 45° ~ 60°. The downward lightning leader is modeled by using discrete line charge to consider the exponential distribution of charges through the downward leader. The voltage condition used by Rizk is used to investigate the inception of the upward lightning leader. Different air conditions (relative air density and air humidity) are considered for more practical simulation. The influences of lightning parameters and lightning rod height on the shielding angle are studied. The results shows that, lightning leader parameters, lightning rod height and ground slope have a series effects on the shielding angle of the lightning rod. Based on the results, recommendations are supposed to decrease the lightning stroke to the lightning rod.