Contactless Wideband Current Measurement Based on Tunneling Magnetoresistance Sensor Array for Rectangular Busbar Systems

Current measurements based on magnetic field sensor arrays have attracted a lot of attention due to their convenience in installation and maintenance. However, conventional current transducers of rectangular busbars are primarily designed for the dc and 50-Hz currents. Numerous industrial applications in power systems require novel technologies of ac current transducers with broader frequency ranges. Some research has achieved accurate measurement for high-frequency ac currents but often relies heavily on the known relative positions of the busbars and sensors. Thus, this article proposes a wideband current measurement method without prior knowledge of precise busbar and sensor positions, which consists of two steps. The first step is using the sensed magnetic field at the fundamental frequency to localize busbar positions, which assist in revealing the regularity of magnetic field variation with frequency. The second step is to reconstruct the currents at harmonic frequencies using the sensed magnetic field at different frequencies and busbar positions. The proposed method is demonstrated for the experiments involving different arrangements of busbar systems, and the performance of the designed wideband current measuring device is verified through experiments.