Impedance of earth return in ground

Definition according to Cigré guide 531 chapter 4.2.1, parameter $z_g$.

Symbol
$z_{earth}$
Unit
$\Omega$/m
Formulae
$\frac{\omega \mu_0 \mu_{earth}}{2\pi} \left(\ln\left(\frac{L_{earth}}{r_{e4}}\right)-\frac{4}{3} m_{earth} L_{cm}\right)$
Used in
$z_{ss}$