Calculates base-current depending on the choice of units.
"pu":
I_base = S_nom/V_nom;"SI":
I_base = 1;
function baseI extends Icons.Function; input Base.Types.Units units "SI or pu"; input SI.Voltage V_nom "nom voltage"; input SI.ApparentPower S_nom "apparent power"; output SI.Current I_base "base current"; end baseI;