Harmonic Mitigation of an Improved High Voltage Current Source for On-Site System Calibration of High Voltage Transformer Loss Measurement Systems

This paper proposes an open-loop technique that mitigates the harmonic distortion in high load currents for onsite system calibrations of high voltage transformer loss measurement systems. The harmonic distortion induced by the current transconductance amplifier and current injector poses high burden on the feedback current correction loop and thus may compromise the measurement accuracy. Accordingly, a harmonic mitigation technique is introduced through online system identification and open-loop anti-harmonic injection. This methodology significantly reduces the THD in the load current from 0.3% to less than 0.022%.