Research of on-line calibration for DC electronic current transformer

With popular application of direct current (DC) transmission system, the DC electronic current transformer (ECT) is studied broadly. But the worse exchangeability and nonlinearity, and the stability of long-term operation all still in exist for DC ECT. So in this paper the on-line calibration method is proposed in order to solve existed problems. The giant magnetoresistance based DC ECT is proposed at first, and then the urgency of on-line calibration are discussed. After that, a novel on-line calibration method is designed. In order to verify the validity of calibration method, an intelligent calibration testing platform is designed and manufactured. The performance of on-line calibration method is illustrated in lab. The realization of on-line calibration will be helpful for the improvement of accuracy and long-term operation of DC ECT.