[ I_f = \fracV_thZ_th ] where ( V_th ) is the prefault voltage at the fault point (usually 1.0 pu), and ( Z_th ) is the Thevenin equivalent impedance seen from the fault point (resistance + reactance). In high-voltage systems, resistance is often neglected, giving:
( Z_th = 0.01 + 0.08 = 0.09 , \textpu )
( I_f = 1.0 / 0.09 = 11.11 , \textpu )