Current sensing transducer for power line current measurements

Claim 1

A current sensing transducer comprising: a conductive current divider having opposite terminal ends for series connection to a current component to be sensed, said current divider including two conductive members in mutually insulated relationship with each of said members having opposite terminal ends for separate series connection to two line currents defining said current component to be sensed, each of said conductive members further having a major current path and a branch current path for conducting a fractional current having a predetermined proportional value relative to one of said separate line currents; a compensated transformer including a magnetic core magnetically resonsive to said fractional current of each branch current path so that each branch current path forms a primary winding thereof, and further including first and second secondary windings inductively coupled to said magnetic core; amplifier means including an input responsive to an output of said first secondary winding and further including an output connected to said second secondary winding so as to control current supplied to said second secondary winding for producing a compensating magnetic flux substantially opposing a flux induced into said magnetic core by each fractional current in response to line current flow through each of said two conductive members of said current divider; and output terminal means responsive to said current supplied to said second secondary winding for producing a current responsive analog signal representative of said current component to be sensed.