$U_e$ is the operating phase-to-ground voltage of the system.

Symbol
$U_{\mathrm{e}}$
Unit
kV
Formulae
$\frac{\sqrt{3} U_{\mathrm{o}}}{3}$three-phase system
$\frac{U_{\mathrm{o}}}{2}$two-phase system
$U_{\mathrm{o}}$single-phase system, DC system
$U_{\mathrm{o}}$
Used in
$CC$
$E_{\mathrm{stress}}$
$I_{\mathrm{C}}$