An efficient method for energy harvesting from overhead insulated shield wires based on a magnetically controlled reactor with active tuning

Abstract

Harvesting energy from insulated shield wires using a tuning reactor is an effective way to supply power to large-scale online monitoring devices installed on high-voltage overhead transmission lines. However, significant fluctuations in equivalent parameters induced by adverse meteorological conditions cause overvoltage, posing challenges to conventional tuning reactors that rely only on inherent material characteristics for self-regulation. To address this problem, this study presents a magnetically-controlled energy harvesting reactor with active tuning for overhead insulated shield wires. In addition to the high- and low-voltage windings, a control winding is added to the low-voltage core side to adjust saturation by injecting an external DC component, allowing active inductance adjustment and limiting overvoltage caused by large fluctuations in equivalent parameters. Field-circuit coupling simulations show that the maximum power under a rated insulation level of 28.5 kV is 985.8 W. Under extreme ice conditions, the maximum power increases to 1281.42 W. However, the voltage across the high-voltage side of the energy harvesting reactor rises to 33.43 kV, exceeding the rated insulation level. After applying the control winding, the voltage on the high-voltage side decreases to 28.42 kV, the maximum power reduces to 929.30 W, and the maximum magnetic flux intensity increases from 1.04 T to 1.44 T. Experimental results from a reduced-scale model verify the effectiveness of the proposed reactor in handling adverse meteorological conditions. The proposed method enhances the robustness and engineering applicability of energy harvesting from overhead insulated shield wires.