Development of a low-cost generator for the testing of current transducers under non-sinusoidal conditions

Current transducers for AC power systems applications are usually calibrated by applying a sinusoidal current and comparing its output with that of a reference current transducer. Changing the excitation signal frequency, allows evaluating the frequency response function of the transducer. However, this test implies the linearity of the transducer or assumes a purely sinusoidal input during operation. Actually, for many years this is no longer representative of the actual working conditions occurring in typical distribution grids, because of the increasing penetration of power electronics, diffuse generation, nonlinear loads, etc. Hence, in order to achieve a more accurate characterization process able to consider also nonlinear phenomena, it is mandatory to investigate the behavior of current transducers with a realistic input signal. In this paper, a low-cost current generator allowing the testing of current transducers with complex excitations in the frequency band from 16 Hz to 2 kHz is presented. A metrological characterization of the proposed generator is also provided.