A further look at dynamic electro-geometrical model: Its fundamentals and implementation

Abstract

The rolling sphere method for air termination placement on a structure is easy to apply, but it cannot be used to determine the probability of lightning strike to different points on the structure. The dynamic electro-geometrical model (DEGM) using numerical methods can be implemented to evaluate the interception efficiency of various air termination systems. The DEGM is implemented using the probability function of lightning current distribution which has a discontinuity at 20 kA. This study proposes a way to remove the discontinuity by the introduction of a continuous step function. The effectiveness of various centrally positioned air terminations on structures was also examined. Mesh air terminations are typically installed directly on the roof of protected structures. Using DEGM concept, result shows that lifting the mesh network by the penetration depth does not significantly improve the interception efficiency of the air termination network for a gable roof structure.

Keywords

• Dynamic electro-geometrical model
• Lightning protection system
• Interception efficiency
• Numerical methods
• Lightning strike probability
• Lightning current distribution