A Monitoring Equipment Charging System for HVTL Based on Domino-Resonator WPT with Constant Current or Constant Voltage Output

The domino-resonator wireless power transfer (WPT) system is designed in this work to harvest energy from the magnetic field around a 110-kV high voltage transmission line (HVTL) and transmit the power to the online monitoring equipment continuously over 1.1 meters insulation distance. Each domino-resonator is evenly spaced and is embedded inside totally sealed insulation discs. The theoretical analysis shows that the constant voltage (CV) mode and the constant current (CC) mode can be realized by adjusting the receiver's switch state, which can meet the battery's CV and CC charging requirements. Such a method cancels the communication between the transmitter and the receiver. The finite element simulation results show that the influence on the electric and magnetic field intensity distribution near the insulator can be negligible. Finally, a 30W prototype with an output voltage of 7V is built. The experimental results show that the fluctuation of output voltage (CV mode) and output current (CC mode) is less than 6% and 7%, respectively. The maximum efficiency is higher than 40% when the transmission distance is 1.1m, and the number of coils is 12.