11. A 20-kVA 8000/277-V distribution transformer has the following resistances and reactances: R₁ = 32 Q, X₁ = 45 Q, R2 = 0.05 Q, X₂ = 0.06 Q, Rc = 250 kQ, Xm = 30 kQ The excitation branch impedances are given referred to the high-voltage side of the transformer. a. Find the equivalent circuit of this transformer referred to the high-voltage side. b. Find the per-unit equivalent circuit of this transformer. C. Assume that this transformer is supplying rated load at 277 V and 0.8 PF lagging. What is this transformer's input voltage? What is its voltage regulation? [8290 @ 0.55° V,3.63%] d. What is the transformer's efficiency under the conditions of part (c)? [95.6%]