Mutual impedance of shield

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

Symbol
$z_{e4}$
Unit
$\Omega$/m
Formulae
$\frac{z_{sc,m} z_{sh,m}}{z_{sc,o}+z_{sc,sh}+z_{sh,i}}$
Related
$z_{sc,m}$
$z_{sc,o}$
$z_{sh,i}$
$z_{sh,m}$
Used in
$z_{cc}$
$z_{cs}$