A novel contactless current sensor for the two-core cable based on TMR chips

In recent years, the introduction and application of magnetic field sensor chips in the field of power system measurement has greatly improved the Contactless current measurement technology based on magnetic field chips. However, the currents of the two conductors of two-core cable are equal and opposite, showing zero magnetic field to the outside, making the traditional method of inverting current based on magnetic field invalid. In this paper, a noncontactless two-core cable current sensor is proposed based on four uniaxial tunnel magneto resistance (TMR) chips. According to the Biot-Savart law, the current of two core cable can be directly deduced by the magnetic induction intensity obtained by the four uniaxial TMR chips. The results show that the assembly angle of the sensor does not affect the results, which brings less constraints to the installation of the sensor. Simulation models and examples were established and analyzed to verify the accuracy and efficiency of the proposed contactless current sensor.