The ratio should be : (132kV/Root3) / (110V/Root3); The accuracy class is as per your requirement; there are various accuracy classes available for metering application as well as for protection application. The burden rating in VA should be as per your requirement (i.e.) it should be as close as possible, but not less than the total load to be connecetd to the secondary side of this CVT. Please note that the transformer rating on the primary side (25MVA as you have mentioned) no way influences the CVT sizing. It is independant.

sir,

I would like to add that Vf-voltage factor is also to be considered.rise in voltage in healthy phase when fault occure in other phase.It will depend on type of earthing and it's impedance