A 60-Hz generator is rated 500 MVA, 20 kV, with subtransient reactance X" =0.2 per unit. It supplies a purely resistive load of 400 MW at 20 kV. The load is connected directly across the terminals of the generator. If all three phases of the load are short-circuited simultaneously, find the initial symmetrical rms current in the generator in per unit on a base of 500 MVA and 20 kV.