A $400-$MVA, $240-$kV$/24-$KV$,$ three$-$phase $Y-$ transformer has an equivalent series impedance of $1,2+j6$ per phase referred to the high$-$voltage side. The transformer is supplying a three$-$phase load of $400-$MVA, $0,8$ power factor lagging at a terminal voltage of $24$ kV $($line to line$)$ on its low$-$voltage side. The primary is supplied from a feeder with an impedance of $0,6+j1,2$ per phase.

a$.$ Determine the line$-$to$-$line voltage at the high$-$voltage terminals of the transformer and the sending$-$end of the feeder. $(40$ pts$)$

b$.$ With transformer rated values as base quantities, express all impedances in per unit. $(20$ pts$)$

c$.$ Working with per$-$unit values, determine the line$-$to$-$line voltage at the highvoltage terminals of the transformer and the sending$-$end of the feeder. PLEASE MAKE HANDWRITTEN SOLUTION