Measurement Method of DC Busbar Current Based on Differential Magnetic Fied

At present, shunts are widely used in current measurement of DC Switch Cabinet. In view of the problems of large volume, narrow measurement range and inability to realize electrical isolation, a busbar current measurement method based on differential magnetic field is proposed. The differential magnetic field is generated by adding shunt slots on the busbar and the back-end circuit is designed to reduce the influence of interference magnetic field on measurement. It has small volume and wide measurement range, strong anti-interference ability, non-contact and other characteristics. Firstly, the measurement method and anti-interference principle are analyzed theoretically, and then the bus simulation model is established in COMSOL to simulate and verify the measurement method, and the transfer relationship between magnetic field and current is calibrated by finite element method. Finally, an experimental platform for busbar current measurement is built, and the experimental results show that the error of the sensor prototype is less than 1.2%, and the influence of the interference magnetic field generated when the interference source is 25mm or more from the sensor can be ignored, which proves the accuracy and anti-interference of the measurement method.