Let choose the base value Sb=100MVA, threephase Vb=345KV line, express the Z=5 + j40 in per unit, express volt?

Zbase = V虏/S = 345虏/(100/3) = 3570 ohm





Zpu = Z/Zbase = 5+j40 / 3570 = 0.0014 + j 0.0112