Impedance of shield inner surface

Definition according to Cigré guide 531 chapter 4.2.2.5 for composite screen, parameter $Z_3$.

Symbol
$z_{e3}$
Unit
$\Omega$/m
Formulae
$z_{sc,i}-\frac{{z_{sc,m}}^2}{z_{sc,o}+z_{sc,sh}+z_{sh,i}}$
Related
$z_{sc,i}$
$z_{sc,m}$
$z_{sc,o}$
$z_{sh,i}$
Used in
$z_{int}$