On the Calibration of Direct-Current Current Transformers (DCCT)

Modern commercial dc current transformers (DCCTs) can measure currents up to the kiloampere range with accuracies better than $1 times 10^{-5}$ . We discuss here a DCCT calibration method and its implementation with commercial instruments typically employed in low-resistance calibration laboratories. The primary current ranges up to 2 kA; in the current range <100 A, the calibration uncertainty is better than $3 times 10^{-7}$ . An example of calibration of a high-performance DCCT specified for primary currents measurement up to 900 A is discussed in detail.