How To Prove CT Connections Using Vectors

     On a Delta - Wye transformer, CT's on the Delta side are wired in Wye and CT's on the Wye side are wired in Delta in order to correct a phase rotation and to filter out zero sequence current. However, how would a commissioning engineer go about proving that the delta CT is wired correctly on the Wye side?  In other words, would polarity of the CT on A phase connect to non-polarity of B or C?  A Linked In forum member shared with me that it is typical that the CT wiring configuration on the Wye side of the transformer should mirror the Delta side winding connections of the transformer.  For taking it an extra step, this could be proven using vectors.

     Dan Scrobe III