Research And Design Of Power Supply For On-line Monitoring Device Of Transmission Line

The safe operation of high-voltage transmission lines is related to social stability and economic development.In China,high-voltage transmission lines are widely distributed and have long distances between transmission lines.Transmission lines will face more difficulties and challenges in their future development.In order to ensure the safe operation of transmission lines,online monitoring of transmission lines is a crucial step.In the research and development field of online monitoring of transmission lines,the issue of power supply has gradually become an important obstacle to online monitoring.In response to the above issues,this article designs an online monitoring equipment power supply system for high-voltage transmission lines based on new technologies of radio frequency energy transmission.The system extracts harmonic energy from the power system,combines radio frequency wireless transmission technology with magnetic induction,and further converts the harmonic energy extracted from the circuit into radio frequency energy.Through radio energy transmission,it crosses the safe distance of high-voltage insulation,The RF energy is transmitted to the RF receiver on the tower,which converts the RF energy into stable DC electrical energy.The main content includes:(1)Overall design of the power supply system for high-voltage transmission line monitoring equipment based on wireless energy transmission technology.The overall design is divided into four parts: the design of harmonic energy extraction circuit for high-voltage transmission lines,the design of power supply for RF energy emission devices,the design of RF energy emission devices,and the design of RF power intake devices.(2)Harmonic energy extraction is based on the basic principles and related parameter design methods of passive filters,and then studied by combining magnetic flux principles.A single tuned filter is proposed to connect the primary side of a three winding transformer,and the secondary side winding adopts hysteresis comparison PWM current control method.By active compensation,a basic compensation current of the same size and opposite direction as the primary side is generated,making the total basic magnetic flux of the iron core equivalent to zero.The primary side of the series transformer presents an approximately zero leakage impedance for the fundamental wave and a high excitation impedance for harmonics.The fundamental current flows smoothly through the transformer,while the harmonics are extracted by another secondary winding.Using MATLAB to establish a simulation circuit model for single-phase harmonic energy extraction,FFT transform the waveform in the obtained harmonic extraction circuit,observe the spectrum distribution,test the effectiveness of the harmonic extraction circuit,and calculate the magnitude of the extracted harmonic energy.(3)The design of the power supply for radio frequency transmission equipment includes the design of coil turns,the selection of iron core materials,and the design of isolation protection circuits.The power supply utilizes the principle of electromagnetic induction to couple harmonic energy,and converts harmonic energy into stable DC voltage through surge protection,rectification and filtering,voltage stabilization,and DC-DC circuits to supply power to RF power transmission equipment.(4)The RF power transmission and RF power acquisition device is designed for the entire circuit using Altium Designer software,and the actual product is made from a PCB board.The RF transmitter chooses to integrate RF wireless transceiver chips,making the entire RF transmission equipment more integrated,intelligent,and miniaturized.The RF acquisition terminal is based on a seventh order rectification voltage doubling topology circuit structure,which enables the RF power acquisition device to have higher output voltage and power,and can provide stable DC power supply for monitoring equipment.Finally,experimental data shows that the power supply system of high-voltage transmission line monitoring equipment based on RF power acquisition and transmission technology can collect the working voltage of high-voltage transmission line safety insulation distance external online monitoring equipment.With the transmission power of RF power transmission equipment reaching 7W,the goal of stable and efficient power supply for online monitoring equipment is achieved.