Cableizer
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Mutual impedance of shield

Definition according to Cigré guide 531 chapter 4.2.1

Symbol
$\mathscr{z}_4$
Unit
$\Omega$/m
Formulae
$\mathscr{z}_{4,sc}$screen
$\mathscr{z}_{4,sh}$sheath
$\frac{\mathscr{z}_{4,sc} \mathscr{z}_{4,sh}}{\mathscr{z}_{5,sc}+\mathscr{z}_6+\mathscr{z}_{3,sh}}$composite screen and sheath
Related
$\mathscr{z}_{3,sh}$
Impedance of sheath inner surface [$\Omega$/m]
$\mathscr{z}_{4,sc}$
Mutual impedance of screen [$\Omega$/m]
$\mathscr{z}_{4,sh}$
Mutual impedance of sheath [$\Omega$/m]
$\mathscr{z}_{5,sc}$
Impedance of screen outer surface [$\Omega$/m]
$\mathscr{z}_6$
Impedance of insulation between screen and sheath [$\Omega$/m]
Used in
$Z_{sg}$
Mutual impedance of shield/sheath with ground return [$\Omega$/m]
$\mathscr{z}_{cc}$
Impedance of conductor [$\Omega$/m]
$\mathscr{z}_{cs}$
Impedance of conductor-screen [$\Omega$/m]