Comparison of AC Power Referenced to Either PJVS or JAWS

The results of a comparison on active power meter calibrations at the National Institute of Standards and Technology (NIST) using a source of AC power referenced to either a programmable Josephson voltage standard (PJVS) or a Josephson arbitrary waveform synthesizer (JAWS) is presented. The measurements were made at 60 V RMS, 5 A RMS, and 50 Hz at a power factor of 1.0. The estimated uncertainty of the active power applied to a meter under test (MUT) of the two system configurations is within $2\ \mu \mathrm{W}/\text{VA}\ (\mathrm{k}=1)$, and the comparison results demonstrate that the two system configurations agree to within 1 part in 106 for applied voltage, current, and phase. A discussion of the measurement techniques and major sources of error are given.