A Wide Range Current Comparator System for Calibrating Current Transformers

This paper describes a new measurement system for the calibration of current transformers at 60 Hz for all ratios up to 10000/5 and higher and at four times rated current. For ratios up to 1200/5, no reference transformer is needed and the system is accurate to five parts per million (ppm). Most higher ratios can be measured using only one reference transformer. Included is an example of how a laboratory could use such a system to measure all ratios up to 8000/5, requiring a calibration of only one reference transformer on one ratio (4000/5).