Electric-field Energy Harvesting for High Voltage Cables Based on Induced Voltage of Metallic Sheath

Distributed monitoring devices for power cables require stable power supply. Traditional power supply methods require frequent battery replacements, which brings inconvenience to the maintenance. During the operation of high voltage (HV) single-core cables, induced voltage is generated on the metallic sheath, forming an electric field with the ground. This electric field can serve as an energy source for electric-field energy harvesting (EEH). First, this paper introduces the principle of EEH for HV cables and establishes a model for the induced voltage on the metallic sheath. Second, a 220 kV single-core HV cable system is simulated to investigate the impact of grounding methods on the induced voltage, and the optimal placement of EEH electrodes is derived. Furthermore, an EEH experimental platform for HV cables is constructed to analyze the effects of electrode length and sheath voltage on EEH output. Finally, the actual charging power of the EEH system is tested. When the metallic sheath voltage is 300 V, a 30 cm EEH electrode achieves an average charging power of 2.07 mW for a 22μF capacitor. The proposed method provides 2.07 mW power with minimal space requirement and low-cost, demonstrating significant potential for practical applications.