Investigation of Wireless Power Transfer for Smart Grid On-line Monitoring Devices under HV Condition

Abstract Magnetically coupled resonant wireless power transfer (WPT) has been employed in many applications, such as wireless charging of portable electronic devices and electric vehicles. This technology can also provide solutions for power transfer in complex environment and special scenario with mid-range transfer distance and acceptable transfer efficiency. In this paper, a mid-range WPT system is designed to provide an effective solution for power supply to smart grid on-line monitoring devices in high voltage (HV) on-site condition. Both the model, design, and experimental implementation of a two-coil system are represented. To find out the transfer characteristic of the proposed mid-range WPT system, the circuit model, exciting frequency, coupling, output power and transfer efficiency are analyzed based on the circuit and magnetic principles. Some key points about the optimal working area for the mid-range WPT system are demonstrated. Finally, a prototype system with transfer distance 1.1 meter for 110 kV HV power cables is built to verify the effectiveness of the regular law of system. By carefully tuning the circuit parameters, the prototype is able to deliver 20W power through 1.1 meter distance with 20.23% efficiency.