Rated Power

kVA

Primary Voltage

kV

Secondary Voltage

V

Impedance

%

Primary Current

A

Secondary Current

A

Fault Current

A

$$I_{primary} = {P_{kVA} \over {\sqrt{3}V_{primary}}}$$
$$I_{secondary} = {P_{kVA} \over {\sqrt{3}V_{secondary}}}$$
$$I_{fault} = {I_{secondary} \over {Z_{imp}}}$$

References and further information:

Transformer books