Self impedance of metal screen

Definition according to Cigré guide 531 chapter 4.2.3.5 (with earth return).

Symbol
$Z_{s}$
Unit
$\Omega$/m
Formulae
$R_{s} + 1.0 i X_{s}$symmetric system
$R_{earth} + R_{s} + 1.0 i X_{s}$with earth return