Fault current: PE Power Transmission and Distribution practice question

A distribution substation is fed from a 115 kV utility system whose available three-phase short-circuit level at the substation high-side bus is 1,500 MVA. The substation transformer is rated 30 MVA, 115 kV Δ / 12.47 kV grounded-wye, with a leakage impedance of 9% on its own rating. Neglecting resistance, pre-fault load current and motor contribution, the three-phase bolted fault current on the 12.47 kV bus is most nearly: