Chapter 3, Problem 3.34P

Three single-phase, two-winding transformers, each rated $\text{45}0\text{MVA},\text{ 2}0\text{kV}/\text{288}.\text{7 kV},$ with leakage reactance ${\text{X}}_{\text{eq}}=0.\text{1}0\text{ per unit},$ are connected to form a three-phase bank. The high-voltage windings are connected in Y with a solidly grounded neutral. Draw the per-unit equivalent circuit if the low-voltage windings are connected (a) in $\Delta$ with American standard phase shift or (b) in Y with an open neutral. Use the transformer ratings as base quantities. Winding resistances and exciting current are neglected.