$400-$kV$,50$Hz$,$ three phase transmission line is $60$ km long. The resistance per phase is $0\mathrm{.}2$ per km and the inductance per phase is $1\mathrm{.}2$ mH per km$.$ The shunt capacitance is negligible. Use the short line model to find the voltage and power at the sending end, the voltage regulation and efficiency when the line is supplying a three$-$phase load of $500$ MVA at $0\mathrm{.}9$ power factor lagging at $400$ kV$.$