A Three-Phase Power Source with Low THD for Energy Meters Calibration

The paper presents an experimental three-phase electronic phantom power source with special requirements, designed for calibrating mostly electronic energy meters. The three-phase power calibrator arrangement generates a variable phantom power of up to 19.2 kVA per phase. Two different power amplifiers, i.e. a voltage and a transconductance amplifier, and other individual components of the power calibrator are introduced and explained. A control method suitable for reducing effects of nonlinear periodic disturbances on electrical quantities, i.e. the output waveforms of voltage and current sources, is explained. The focus is on the theory of a modified repetitive control method based on a procedure with a recurrent integral action distributing the controlled signal in a certain number of intervals and subsequently correcting each interval separately and independently of the remaining intervals. Results acquired with the help of the experimental source are presented.