Research on the measurement performance of wide-range current transformer based on zero-flux principle

Due to nonlinear magnetization characteristics of the iron core, the traditional electromagnetic current transformer has a large error in measurement of wide-range current. To optimize the wide-range characteristics of current transformer, this article proposes a wide-range current transformer structure based on the zero-flux principle. Composite iron core is used as the main iron core and passively compensates the current transformer so that the main iron core operates in an approximate zero-flux state, which reduces transmission error of the current transformer and broadens the range of current transformer. By analyzing the error transfer function and using Ansys finite element simulation software, it is proved that the current transformer has high measurement accuracy and good wide-range characteristics, meeting the accuracy requirements of 0.1s-level current transformer under a wide range of working conditions (0.1%I_N~200%I_N).