Highly Sensitive Magnetoelectric Sensor for Characteristic Current Detection in Smart Grid

In smart grid, the topological relationship between the transformers and the consumers in a low-voltage distribution network is crucial for powerline loss analysis, fault locating, and power dispatching, etc. The state-of-the-art method for topological relationship identification relies on the precision detection of weak characteristic current with a frequency of ~833 Hz. In this work, we design a magnetoelectric (ME) sensor based on the cantilever beam that made of Metglas/Ni/PZT composite and NdFeB permanent magnets, whose second-order resonant frequency is comparable to the frequency of characteristic current. Due to the resonant-enhanced sensitivity of the ME sensor, weak characteristic current at $\mu $ A level is detectable with a high sensitivity of about 111 mV/A in a nonintrusive manner. The proposed ME current sensor doesn’t require power supply and is able to detect weak currents as low as $0.43~\mu $ A. Theoretical calculations, finite element simulations, laboratory, and field experiments have verified the effectiveness of the sensor, showing great potential for practical applications in noninvasive characteristic current detection.