Mutual impedance between shields/sheaths of inner and outer cables with ground return

Definition according to IEEE 575-2014 Annex E.1.4.3.2

Symbol
$Z_{oig}$
Unit
$\Omega$/m
Formulae
$+j \omega 2{\cdot}{10}^{-7} \ln\left(\frac{1}{S_m}\right)$