How would the orientation of a CT have anything to do ground potentials?
CTs should be connected so that the wye point of the CTs points toward the protected zone and other side gets connected to the polarity terminal of the relay. Same goes for a neutral CT, it should be grounded on the equipment side and connected to the polarity of the relay on the side away from the equipment. It's nice when it happens that the polarity of the CT connects to polarity of the relay, but means nothing really. For the relay connections, forget that the CTs even have polarity marks, just go with the correct wiring relationships. For your testing, current from ground to the X0 terminal should be in phase with current from the CT into the relay.