The ratio of full load current to short circuit current = 1/6
Xsc = j/(1/6)
External reactance required = j*((1/6) - 0.06))
= j*0.106 pu
Full load current = (40*1000)/(√3*15)
= 1539.6 A
Per unit reactance = j*0.106 = (I*Xr)/V
j*0.15 = (1539.6*Xb)/((15/√3)*1000))
= 0.60 ohm
EXAMIANS