Busbar sizing

Hi all

I would like to know how to size busbar with the following parameters.

The busbar is required for a transformer secondary to feed to the distribution board.

transformer is 3 phase 2MVA 11kV/.400 with powerfactor of 0.95. Impedance rating is 7.5%. Therefore the primary current is 110A with short circuit rating of 1473A.

Secondary current is 3038.68A and short circuit current is 40.5kA. I used the impedance level to calculate this. I want to used a current density of 1A/mm2. The ambient temperature is 40 deg and rise of 50 deg.

I would like to know will i use the 40.5kA to size the busbar or the operating current of 3038.68A? Also how can i size it taking into account these factors.