Effect of Frequency-Dependent Soil on the Propagation of Electromagnetic Fields Radiated by Subsequent Lightning Strike to Tall Objects

In this paper we have studied the propagation effect of frequency-dependent soil (FDS) on the far vertical electric fields radiated by subsequent lightning strike to tall objects with heights from 50 to 300 m. It is found that the field propagation attenuation along FDS is obviously less than that case where the parameters are assumed to be constant (low-frequency conductivity at 100 Hz, LFC) and with the decrease of LFC, the corresponding field attenuation increases. When LFC is equal to or larger than 0.01 S/m, the effect of FDS can be ignored. However, when LFC is 0.0001 S/m, the field peak for FDS may reach as much as 2.5 times of that earth with LFC for strike to a 300-m-tall object.