KRISS-NRC Intercomparisons of Calibration Systems for Instrument Transformers With Many Different Ratios at Power Frequency

An intercomparison of the calibration systems for instrument transformers between the Korea Research Institute of Standards and Science (KRISS) and the National Research Council of Canada (NRC), with many different ratios at 60 Hz, was performed using six portable transfer standards. The portable transfer standards consist of two current transformers (CTs) with current ratios of 5 A/5 A up to 20 000 A/5 A and four voltage transformers (VTs) with voltage ratios of 110 V/110 V up to 66 000 V/110 V. The comparison results for the CT calibration systems between the two institutes are in good agreement within 10times10^-6 for ratio and 10 murad for phase for all the current ratios. The comparison results for the VT test systems also indicated good agreement within 35times10^-6 for ratio and 35 murad for phase for all voltage ratios.