The positive sequence reactance of the cable can be calculated from the following equations. When a non-magnetic armour is present, $d$ is replaced by $d_e$.

Symbol
$X_{\mathrm{s}}$
Unit
Ω/m
Formulae
 $2.0 \cdot 10^{-7} \omega \ln{\left (\frac{2 s_{\mathrm{c}}}{d_{\mathrm{s}}} \right )}$ 2 (and 2 x 2) single-core cables and 3 single-core cables in trefoil formation, sheath bonded at both ends $2.0 \cdot 10^{-7} \omega \ln{\left (\frac{2.5192599598948 s_{\mathrm{c}}}{d_{\mathrm{s}}} \right )}$ 3 single-core cables im flat formation with regular transposition, sheath bonded at both ends $2.0 \cdot 10^{-7} \omega \ln{\left (\frac{2 s_{\mathrm{c}}}{d_{\mathrm{s}}} \right )}$ 3 single-core cables im flat formation without transposition, sheath bonded at both ends $1.25 X_{\mathrm{s}}$ single-core cables with unknown variation of spacing between sheath bonding points $\frac{X_{\mathrm{S1}} a_{\mathrm{S1}} + X_{\mathrm{S2}} a_{\mathrm{S2}} + X_{\mathrm{S3}} a_{\mathrm{S3}}}{a_{\mathrm{S1}} + a_{\mathrm{S2}} + a_{\mathrm{S3}}}$ single-core cables with known variation of spacing between sheath bonding points $2.0 \cdot 10^{-7} \omega \ln{\left (\frac{2 s_{\mathrm{c}}}{d_{\mathrm{s}}} \right )}$ three-core cables with each core in a separate lead sheath and armoured or pipe-type cables $0.002893 f \operatorname{log}{\left (\frac{s_{\mathrm{c}}}{GMR} \right )}$ 4 single-core cables with equal distance or multi-core cables with common screen or sheath $0$ 1 single-core cable
Related
$a_{\mathrm{S1}}$
$a_{\mathrm{S2}}$
$a_{\mathrm{S3}}$
$d_{\mathrm{e}}$
$d_{\mathrm{s}}$
$GMR$
$\omega$
$s_{\mathrm{c}}$
$X_{\mathrm{S1}}$
$X_{\mathrm{S2}}$
$X_{\mathrm{S3}}$
Used in
$\lambda_{\mathrm{1cb}}$
$M_{\mathrm{e}}$
$N_{\mathrm{e}}$
$P_{\mathrm{cc}}$
$Q_{\mathrm{cc}}$
$RF$