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 μ 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 0.43μ 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.