Module of the rated currents - transformer:

The transformer of the Face(Figure) 2 is a transformer of type Delta-Y (the neutral of Y is grounded). The rated output is of 1500 kVA, the rated voltages are 12.5 kV in the primary and 480 V in the secondary and the equivalent reactance of direct sequence of the transformer is 5 %.

1-What is the module of the rated currents associated with the rolling-ups in the primary?

2-What is the number format which corresponds to this connection of the transformer according to the principle of the clock?

3-What is the rate of the rolling-ups between the primary and secondary?