Measured Distortion of Current Waves and Electrical Potentials With Propagation of a Spherical Wave in an Electromagnetic Field

It is important to analyze the phenomena connected with an electromagnetic wave that propagates spherically. A typical example is the propagation of a current perpendicular to the ground, such as a surge current that propagates along a tall structure like a transmission tower. Some distinguishing characteristics reported for a current propagating on a vertical conductor are the attenuation or distortion of the waveform. However, no measurements have been performed by which any distortion of the current waveform and the electric potential on the conductors can be quantitatively characterized. This paper presents the results of experiments to determine the current distortion on a straight wire conductor and the electric potential perpendicular to the conductor. The current waveform was distorted while propagating, although there was no change in the potential waveform. Finite-difference time-domain method results were in good agreement with the experimental results in terms of both the current and potential waveforms.