Q$-1$ A $100-$KVA $8000/277-$V distribution transformer has the following resistances and reactances: R$=522$ Rs $=0\mathrm{.}00522=$ X$,=6$ X$,=0\mathrm{.}00622$ Rc $=50$ kO$2$ X $=10$ k$2=$ M 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 low$-$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 $0\mathrm{.}85$ PF lagging. What is this transformer's input voltage? What is its voltage regulation? $($d$)$ What are the copper losses and core losses in this transformer under the conditions of part $($c$)?($e$)$ What is the transformer's efficiency under the conditions of part $($c$)?$