Problem No. 5 A 40-MVA, 20-kV/400-kV, single-phase transformer has the following series impedances: Z1= 0.9 + /1.8 0 and Z2 = 128 + /288 0 Using the transformer rating as base, determine the per unit impedance of the transformer from the ohmic value referred to the low-voltage side. Compute the per unit impedance using the ohmic value referred to the high-voltage side