The Effect of Direct Lightning Shielding Rod on Lightning Electromagnetic Fields Aboveground

A practical new type direct lightning shielding rod is designed to reduce the electromagnetic radiation produced by lightning stroking to Franklin lightning rod in the paper. The Finite-Difference Time-Domain (FDTD) method is adopted for analyzing. It is the shielding layer that affects the electromagnetic fields and the insulating medium make no difference. All the electromagnetic fields amplitude obtained decrease for the shielding layer existing, regardless of any condition, but the extent is different. That is, the effect on the horizontal electric field is most noticeable, the vertical electric field comes second, minimum the azimuthal magnetic field. All the field components are affected by shielding layer height and the distance between shielding layer and lightning channel, but not significantly by the shielding layer grounding depth. The shielding effect is more obvious with lower ground conductivity, but the ground relative permittivity makes no difference.