Impedance between cable k and p in ground

Definition according to CIGRE TB 531 chap. 4.2.1

Symbol
$Z_{kp}$
Unit
$\Omega$/m
Formulas
$\frac{\omega \mu_{0} \mu_{E}}{2\pi} \left(\ln\left(\frac{D_{E}}{d_{kp}}\right)-\frac{2}{3} m_{E} \left(L_{ck}+L_{cp}\right)\right)$