A planar-coil-based current transducer used in distribution power system

For measuring currents flowing in three-phase rectangular-shaped busbars, in this paper, a planar coil with air core is used as a current sensing unit. The vector potential of the busbar and the electromotive forces of the planar coil for single- and three-phase currents are calculated with a numerical integration arithmetic. The relative error caused by adjacent busbars was simulated when the transducers were used for the three-phase current measurement. The simulation results show that the relative error induced by the adjacent busbars is less than 2%. Planar-coil-based current transducers enclosed with silicon rubber insulator are developed. The successful field trial of the transducers for more than four years shows that the transducers can meet the field requirement.