Self reactance of screen/sheath

The equation for a single phase with earth return is from the Cigré guide 531 chapter 4.2.3.5.

Symbol
$X_s$
Unit
$\Omega$/m
Formulae
$\frac{\omega \mu_0}{2\pi} \ln\left(\frac{2s_c}{d_s}\right)$default cable without transposition
$\frac{\omega \mu_0}{2\pi} \ln\left(\frac{2a_m}{d_s}\right)$default cable with regular transposition
$\frac{\omega \mu_0}{2\pi} \ln\left(\frac{2s_{cm}}{D_{encl}-t_{encl}}\right)$PAC/GIL
$1.25X_s$unknown variation of spacing between sheath bonding points
$\frac{a_{S1} X_{S1}+a_{S2} X_{S2}+a_{S3} X_{S3}}{a_{S1}+a_{S2}+a_{S3}}$known variation of spacing between sheath bonding points
$\frac{\omega \mu_0}{2\pi} \ln\left(\frac{2L_{earth}}{d_e}\right)$1 cable with earth return