Topology Optimization and Magnetic Field Calculations of Magnetic Shield Structure of Microcurrent Sensor

Leakage current is an indispensable basic parameter for the insulation state of power equipment. In order to improve the reliability of power equipment insulation state perception, the leakage current measurement results must be accurate, stable and reliable. Leakage current measurement belongs to the precision measurement category of high voltage, strong magnetic field and small current, generally μA or mA level, which is susceptible to external environment interference. Leakage current is usually measured using a non-contact electromagnetic induction element, so this sensing device is very sensitive to external magnetic fields. Therefore, it is of great significance to study the efficiency and topology optimization of magnetic shield structure of microcurrent sensor. In order to solve the technical problem of the weak ability of the microcurrent sensor to resist the power frequency magnetic field interference, the interference characteristics of the external magnetic field to the working magnetic field of the microcurrent sensor in the complex system substation environment are studied. The shielding effect of magnetic shielding structure of leakage current detection equipment under different schemes is further studied, and the optimal shielding structure is proposed. The research on magnetic shielding technology in this paper can provide theoretical basis for accurate measurement of leakage current.