Study on Magnetic Field Interference Characteristics of Difference Magneto-optical Current Transformer

Magneto-optical current transformer has the defect of poor anti-interference ability. In this paper, the interference characteristics of differential magneto-optical current transformer are studied based on the background of interphase magnetic field interference in three-phase power system. By establishing the magnetic field interference model, the anti-magnetic field interference characteristics of the differential magneto-optical current transformer are studied. The research shows that there is a zero magnetic field interference point in the difference magneto-optical current transformer and the zero-interference angle presents a specific distribution law. When the transmission light path of the difference magneto-optical current transformer degenerates to a square arrangement, the value of magnetic field interference has nothing to do with the distance of interference current. Moreover, the square structure makes it have zero-interference angle at a specific angle. The analysis shows that when the interference current deviates from zero-interference angle, the differential magneto-optical current transformer has fault tolerance within a certain range of distance and angle. And it can still meet the requirements of measurement accuracy under the influence of interference current. The simulation results are consistent with the theoretical analysis, which proves the correctness of the theoretical analysis. This research can provide a useful idea for the design of anti-phase magnetic field interference for the application of differential magneto-optical current transformer in power system.