power system machine problem

1. Machine Problem No.1:
Design the protection of a three-phase, 50-MVA, 230/34.5 kV power transformer using
available standard CT ratios. The high-voltage side is Y-connected and the low-voltage side is ∆-
connected. Specify the CT ratios, and show the three-phase wiring diagram indicating the CT polarities.
Determine the currents in the transformer and the CTs. Specify the rating of an autotransformer, if one
is needed.