Extension of voltage range for power and energy calibrations

A special purpose ac voltage divider system with ratios of 600, 480, 360, 2 77, and 240 V to 120 V has been developed to extend the range of primary el ectric power calibrations from 120-600 V at 50 and 60 Hz, The developmental goal has been to realize ac voltage scaling within 5 mu V/V overall relati ve uncertainty. By employing a technique consisting of a special two-stage resistive divider compensated with an active circuit, the overall uncertain ty achieved after calibration is 4 mu V/V.