A 600 V AC Voltage Amplifier for Power Measurements

A voltage amplifier composed of three cascaded -10:1 gain sections has been developed to extend the voltage range of primary electric power calibrations from 120 to 600 V over the 50-400-Hz frequency range. The gain and phase errors of each amplifier section are continuously measured and corrected in situ using a permuting impedance measurement technique. The amplifier design approach, measurement principles, and initial performance results are presented.