A 3-phase, 50 Hz, 160 km long overhead line supplies 1000 kW at 11 k V, 0·8 p.f. lagging. The line resistance is 0· 0 05 Ω per phase per km and line inductance is 0·05 mH per phase per km, the line susceptance is 10-05 S per phase per km. Calculate the sending end voltage, voltage regulation and efficiency of transmission