An Efficient Compensation Algorithm for Current Transformer Saturation Effects

Abstract

Current transformer (CT) saturation leads to inaccurate current measurement and, therefore, may cause malfunction of protective relays and control devices that use currents as input signals. This paper introduces an efficient compensation algorithm capable of converting from a sampled current waveform that is distorted by CT saturation to a compensated current waveform. Attractive features include quick response time, no cumulative estimation errors, desired sample-by-sample output, independent of CT parameters/characteristics and secondary burdens, and simplicity for online implementation. The accuracy and robustness of the introduced compensation algorithm are demonstrated through extensive test cases reflecting a wide range of variations in fault conditions and CT parameters.