[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - A Synchronized Current-Comparator-Based Power Bridge for Calibrating Analog Merging Units

摘要： A synchronized current-comparator-based power bridge for calibrating analog merging units at power frequencies of 60 Hz and 50 Hz is described. Analog merging units take analog signals from instrument transformers, convert them into digital form, pack the sampled values into Ethernet frames conforming to the IEC 61850-9-2 LE specification and stream the frames to other equipment in a digital substation for further processing. Since the sampled values are used for protection and metering, the merging units need to be calibrated. The expanded uncertainties (k=2) of the described calibration system are estimated to be better than 30 μA/A for magnitude and 60 μrad for phase.