High Sensitivity and Anti-Interference Magnetoelectric Sensor for Characteristic Current Detection in Smart Grid Topological Identification

Topology identification (TI) is one of the key applications in smart grids. One approach involves generating a weak characteristic current signal at 833 Hz through smart meters and detecting it at distribution facilities. Existing current sensors are predominantly broadband devices, making it challenging to detect weak characteristic current signals under strong interference and high attenuation conditions. Current sensors based on magnetoelectric (ME) coupling exhibit resonance enhancement characteristics, offering robust performance with narrow bandwidth, making them suitable for characteristic current detection. This work employs a segmented equivalent circuit model to screen a ME sensor with a variable section structure. Its resonance frequency is 833 Hz, with the ME coupling coefficient of 539.8 V/cm/Oe at resonance, while the -3 dB bandwidth is only 8 Hz, achieving the limit of detection (LOD) as low as 380 fT. Laboratory testing reveals the characteristic current sensitivity of 0.71 V/A and the LOD of 0.1 µA. Field tests demonstrate the sensor's capability to detect characteristic signals amidst attenuation in multilevel power distribution facilities and amidst 50 Hz current interference at the kA level, showcasing broad application prospects.