Development of a Wide-Range Current Transformer Calibration System Based on Digital Comparison Principle

The development of wide-range technology of current transformers (CTs) poses a high challenge to the traceability of metrological performance of CTs. This paper focuses on two matters: (1) the calibration capability of the wide-range CT is insufficient, and (2) the existing technology is unsuitable for automatic calibration. In this paper, the development of a wide-range CT calibration system based on the digital comparison principle is carried out. First, the calibration method for the wide-range CT is proposed, with a measurement range of 0.1%∼200%. Second, a program-controlled wide-range reference CT and a wide-range CT calibrator are developed. Third, a comparative test between the proposed scheme and the traditional method is carried out. The test shows a satisfactory performance of the system introduced.