Imaginary layer of soil

The imaginary layer of soil is used to model a non-isothermal earth surface.

Based on Kutateladze's fictitious layer method (or additional wall method), a non-isothermal earth surface can be modelled with the help of a fictitious earth layer with thickness $d_{im}$. The cable image line source is then placed at distance $L_{cm}+d_{im}$ above the fictitious layer.

The method is based on a paper from 2014 by Sujit Purushothaman.

Symbol
$d_{im}$
Unit
m
Formulae
$\frac{1}{h_{tr} \rho_{4}}$Kutateladze
$\frac{\beta_{T}}{\rho_{4}}$Kenelly (acc. CIGRE Guide 218)
$h_{tr}$
$\rho_{4}$