Impedance of armour inner surface

Definition according to Cigré guide 531 chapter 4.2.1

Symbol

$\mathscr{z}_{pin}$

Unit

$\Omega$/m

Formulae

$\frac{m_{z,ar} \rho_{ar}}{2\pi r_{z4}} \operatorname{coth}\left(m_{z,ar} \left(r_{z5}-r_{z4}\right)\right)-\frac{\rho_{ar}}{2\pi r_{z4} \left(r_{z4}+r_{z5}\right)}$

Related

$m_{z,ar}$

Parameter m of armour

$\pi$

Archimedes' constant $\pi$

$r_{z4}$

Radius of armour (inner) [m]

$r_{z5}$

Radius of armour (outer) [m]

$\rho_{ar}$

Specific electrical resistivity of armour material [$\Omega$.m]