Design of the long-distance wireless power transfer system with multiple relay coils based on loss optimization

This paper proposes a design scheme for a wireless power transfer (WPT) system based on multi-relay coils to solve the power supply demand of 500 kV transmission line online monitoring equipment. The relationship between the operating frequency and the coil loss is established to analyze the influence of the number of relay coils and the coil distance on the transmission performance. The particle swarm optimization model is established with transmission efficiency as the optimization objective. The distribution spacing between coils, the working frequency, and the number of coils are optimized. Based on the equidistant arrangement of relay coils, an optimization scheme of non-equidistant arrangement is proposed. Under the condition of the same number of relay coils, the transmission efficiency of the system is increased by 20.56% and has been verified by experiments. In addition, finite element analysis software has simulated the surrounding high-voltage field strength of the WPT system added to the insulators. The results show that the insulators still meet the insulation standards. The simulation and experimental results show that the proposed scheme can effectively meet the power demand of high-voltage line monitoring equipment.