Research on current transformer error verification system based on digital comparison method

In order to meet the new demand for measuring wide range, mixed $\mathrm{AC} / \mathrm{DC}$, injected harmonics and other wide dynamic current signals of bidirectional power flow after the integration of wind and solar new energy, research on current transformer technology for complex signal measurement is increasing. However, there is currently no relevant research report on error verification of current transformers for wide dynamic measurement. On the basis of traditional current transformer calibration technology, this article designs a current transformer error calibration system based on digital comparison method. The principle of digital comparison method technology is analyzed, and a Nutall self multiplication convolution window double spectral line interpolation algorithm is proposed. The amplitude and phase formulas are derived and corrected. Simulation and experimental data show that the measurement error of the algorithm is better than $10-6$ values, and the measurement accuracy of the verification system is better than ± 0.1%, providing a new idea for error verification of current transformers for complex signal measurement.