Magnetic circuit for current measurement of transmission line

Generally, the measurement of power line current is done by measuring the magnetic field around it, so how to increase the magnetic field at the sensor head is the key to achieve high sensitivity detection. A ferrite magnetic circuit (FMC) system was proposed to improve the conversion efficiency of transmission line current to magnetic field at the sensor head. The FMC is designed as a rectangular structure with a slit in which the sensing head is placed. The magnetic field generated by the current is concentrated at the sensing head by using the high permeability of ferrite. The simulation results shows that the magnetic field in the slit is mainly determined by magnetic permeability, the length and the cross-sectional area of the magnetic bar. It monotonically increases with the increasing of magnetic permeability, and decreased gradually with the slit width increasing. It increased rapidly at first and then increased slowly with the increasing of the cross-sectional area of the magnetic bar. It has a good practical value to improve the sensitivity of optical fiber current sensor.