Isolated Orthogonal Magnetic Energy Harvesting System Around High Voltage Transmission Lines

In order to monitor the environmental conditions around the transmission line and accurately locate faults when they occur,it is necessary to install low-power wireless monitoring equipment to monitor the transmission line and transmit real-time environmental data around the line.However,the power supply of wireless monitoring devices is constrained by their installation location and battery energy.Magnetic energy harvesting is a technology that converts magnetic energy in the environment into electrical energy.By harvesting rich magnetic energy around AC transmission lines,this technology can provide stable electrical energy for wireless monitoring devices.The current research focuses on the harvesting of magnetic energy around transmission lines mostly focus on using different magnetic core material structures to improve the energy density of magnetic energy harvesters and reduce internal losses.However,due to the harvesters’ location being far from the transmission line,there are still problems such as low output energy.Therefore,in view of the low output of the harvesters and the fact that devices often use DC power supply,this thesis proposes an isolated orthogonal magnetic field energy harvesting system to improve the system’s output capacity and achieve the goal of providing electrical energy for low-power wireless monitoring equipment.Firstly,the advantages of wireless monitoring equipment in monitoring the working conditions around high-voltage transmission lines are introduced,and the technical background of energy harvesting technology in supplying power to wireless monitoring equipment on high-voltage transmission lines is introduced.The different types of energy harvesting used around existing high-voltage transmission lines are summarized,highlighting the advantages of isolated magnetic energy harvesting.Finally,the purpose and significance of this study are introduced,and the organizational structure and research content of the full text are given.Next,the working principle of the isolated cylindrical magnetic energy harvester is introduced,and its equivalent circuit is modeled.The impact of different wire diameters on the harvesting power of the magnetic energy harvesting coil is analyzed.At the same time,analyze the effective permeability of the isolated magnetic core,establish an equivalent mathematical model of the magnetic core,calculate the relationship between the effective permeability and the shape of the magnetic core,and clarify the importance of the effective permeability of the magnetic core to the harvester output.Then,the magnetic field distribution under the high-voltage transmission line is analyzed using two-dimensional and three-dimensional calculation models.However,considering the sag effect of long-distance transmission lines,the three-dimensional model is more accurate in analyzing the magnetic field environment at the transmission tower.The complex analysis method is used to calculate the magnetic induction intensity under the transmission line.Taking the magnetic field distribution at a 500 k V transmission line tower as an example,the magnetic field distribution at a location 20 meters from the ground is verified.Then,by comparing the harvesting capabilities of existing isolated magnetic energy harvesters,an "H" type magnetic energy harvester with a large effective magnetic permeability is designed,and an isolated orthogonal magnetic energy harvesting system is proposed.The power expression of the voltage doubling circuit is analyzed using Fourier method,and the output power and maximum power point of the direct resistive load circuit of the isolated orthogonal magnetic energy harvesting system are obtained.The circuit of the power management circuit of the isolated orthogonal magnetic energy harvesting system is designed.Finally,a simulation platform for the magnetic field around high-voltage transmission lines and an isolated orthogonal magnetic energy harvesting system were built.The Helmholtz coils are used to simulate the magnetic field around the transmission line,and the output no-load voltage and load power of the direct resistive load circuit of the isolated orthogonal magnetic energy harvesting system are tested;Perform output voltage testing and LEDs testing on the isolated orthogonal magnetic energy harvesting system with power management circuitry.The feasibility of the isolated orthogonal magnetic energy harvesting system designed in this thesis is verified through testing.57 figures,7 tables and 82 references are included in this thesis.