Study on current transducer based on planer coil

For measuring current in three-phase plate-form busbars, this paper proposed an indirect method that used planar Rogowski coil as the current sensing part. Based on the electromagnetic induction law, Biot-Savart law and the numerical integration arithmetic, the vector potential of the busbar was calculated and the electromotive force of the planar coil for the single phase and three-phase busbar current was deduced. The relative error that was caused by vertical displacement, flat displacement and rotated displacement of coil was measured and calculated when the coil was used for the measurement of plate-form busbar current. The results of the theoretical calculation about the coil have good accordance with the experiments. More than two years of field testing shows that the current transducers based on the planar Rogowski coil proposed by this paper meets the requirement of practicality.