A 600-V AC voltage amplifier for power measurements

A voltage amplifier comprised of three, cascaded, -10:1 gain sections has been developed to extend the voltage range of primary electric power calibrations from 120 V to 600 V over the 50 Hz to 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.