D. The Coupling Model
Several coupling models available in the literature describe
the interaction of EM waves with overhead power lines. The
studies of Nucci et al. [18], Cooray [19], and Nucci et al.
[20] show that many of the models available in the literature
are special cases of a model proposed by Agrawal et al. [21].
The latter authors derived transmission line equations for a
multiconductor system including a reference conductor. To
derive the transmission line equations over finitely conducting
ground we will use an approach similar to that of Agrawal et
al. [21] but modified to take into account the finite conductivity
of the ground. Let us consider a single conductor line over
finitely conducting ground. The relevant geometry is shown
in Fig. 2(a). Consider the Maxwell’s equation related to the
Faraday’s law. This can be written as