The ratio of full load current to short circuit current = 1/5
Xsc = j/(1/5)
External reactance required = j*((1/5) - 0.05))
= j*0.15 pu
Full load current = (30*1000)/(√3*11)
= 1574.6 A
Per unit reactance = j*0.15 = (I*Xr)/V
j*0.15 = (1574.6*Xb)/((11/√3)*1000))
= 0.60 ohm
EXAMIANS