A 50-kVA 13800/208V Delta wye distribution transformer has a resistance of 1 percent and a reactance of 7 percent per unit.
(a) What is the transformers phase impedance referred to the high-voltage side?
(b) Calculate this transformers voltage regulation at full load and 0.8 PF lagging, using the calculated high-side impedance.
(c) Calculate this transformer's voltage regulation under the same conditions, using the per-unit system.