Influence of non-flat terrain on lightning induced voltages on distribution networks

• We have simulated lightning induced voltages above three non-flat terrains with rotational symmetry.
• The lightning induced voltages obtained over non-flat terrains are greater the inclination angle of the terrain is increased.
• The inclusion of finite conductivity causes considerable increments of the induced voltage over non-flat terrains.
• The calculation of lighting induced voltages requires the inclusion of the terrain because the great differences presented compared with the flat ground simulation.

This paper presents the effect of the terrain geometry in lightning induced voltages calculation on power distribution networks. We have calculated the electromagnetic fields over three different non-flat terrains configurations, by means of the Finite Difference Time Domain (FDTD) method in a two dimensional (2D) cylindrical coordinate system. We have simulated a typical distribution network placed over those terrains, and we have calculated the lightning induced voltages over these lines by means of the Agrawal coupling model. The simulated terrains are for finite and infinite conductivity. It can be seen important differences between the lightning induced voltages over non-flat terrain compared with traditional calculation considering flat terrain, specially when the finite conductivity is considered.