Reactance at OA, 3 phase capacitance to ground on HV and LV side

[EddyPach]

Basic questions,
Can somebody provide the formulas to calculate:
the reactance at the OA rating in a 3 phase 126/168/210 MVA, 230 -18 kV power transformer?
the three phase capacitance to ground on the high voltage side?
the three phase capacitance to grond on the low voltage side?

Thanks in advance