Multifunction single core sensor for ground fault application

A ground fault sensing circuit system, comprising:

• a current transformer having a body with an opening having a central axis running along a length of the opening, the current transformer having a first winding and a second winding wrapped around the body and through the opening, the first winding configured to output a first signal and the second winding configured to output a second signal, the body surrounding two parallel conductors that pass through the opening parallel with the central axis and occupy a conductor plane that is coincident with the central axis, the two parallel conductors being substantially equidistant from the central axis;
• wherein the first signal corresponds to a first secondary current in the first winding induced by a magnetic flux in the first winding that is magnetically coupled with a first current in a first conductor of the two parallel conductors;
• wherein the second signal corresponds to a second secondary current in the second winding induced by a magnetic flux in the second winding that is magnetically coupled with a second current in a second conductor of the two parallel conductors;
• and
• wherein the first winding is wrapped around a first half of the body and the second winding is wrapped around a second half of the body, and the first winding is non-overlapped with the second winding;
• and
• a processor coupled to the first winding to receive the first signal and coupled to the second winding to receive the second signal, the processor configured to determine information about at least one of a first current in a first conductor or a second current in a second conductor of the two parallel conductors, based on a combination of the first signal and the second signal.

A ground fault sensing circuit system, comprising:

• a current transformer having a body with an opening having a central axis running along a length of the opening, the current transformer having a first winding and a second winding wrapped around the body and through the opening, the first winding configured to output a first signal and the second winding configured to output a second signal the body surrounding two parallel conductors that pass through the opening parallel with the central axis and occupy a conductor plane that is coincident with the central axis, the two parallel conductors being substantially equidistant from the central axis;
• wherein the body surrounds a third conductor that passes through the opening of the body and is coincident with the central axis;
• wherein the first winding is wrapped around a first half of the body and the second winding is wrapped around a second half of the body, and the first winding is non-overlapped with the second winding;
• wherein a third winding is wrapped continuously around both halves of the body, through the opening, overlapped with the first and second windings, and configured to output a third signal;
• and
• a processor coupled to the first winding to receive the first signal, coupled to the second winding to receive the second signal, and coupled to the third winding to receive the third signal, the processor configured to determine information about at least one of a first current in a first conductor or a second current in a second conductor of the two parallel conductors, or a third current in the third conductor, based on a combination of the first signal in the first winding, the second signal in the second winding, and the third signal in the third winding.