Analysis of Transfer Characteristics of Magnetic-Valve-Type Current Transformer

Current transformer (CT) is widely used as the current measurement tool in power system. However, core saturation is the main reason restricting its application. Magnetic-valve-type current transformer (MVCT) constructs a magnetic valve on the core, and can compensate for the distorted secondary current due to core saturation by measuring the magnetic field intensity of the air gap where the magnetic sensor. MVCT has a certain engineering application prospect because of its simple structure and low cost. In order to further study the transfer characteristics of MVCT, the equivalent cross-sectional area of air gap, which is used to modify equivalent magnetization curve model, is considered. According to the modified equivalent magnetization curve model, the transfer characteristics of MVCT are analyzed. Finite element simulation and experimental results have proved the correctness and effectiveness of the model and analytical expression.