Striking distance calculation for flat ground and lightning rod by a 3D self-organized Leader Propagation Model

Abstract

This study presents the calculation of lightning striking distances to flat ground and to lightning rod with a 3 dimensional (3D) self-organized negative downward stepped Leader Propagation Model (LPM). For various scenarios, firstly, the lightning striking distance to flat ground, which is defined as the quotient of critical breakdown electric field divided by leader tip potential just before it touches the ground, is evaluated. Secondly, the lightning striking distance to lightning rod is determined while positive upward leader inception and propagation criteria are considered. It is found that the striking distance is well correlated to the leader tip charge density rather than total charge deposited in leader channel. With a presumed linkage between leader tip charge density and the return stroke peak current, the striking distance is correlated to return stroke peak current. The results show that the striking distance to flat ground calculated by the present method is shorter in lower peak current range than those done by existing ones. In the meantime, the striking distance to lightning rod is in accordance with previous studies.