Research On On-Line Energy Acquision Method Of Double Magnetic Circuit Based On Adjustable Impedence

With the vigorous development of smart grids in China and the construction of UHV transmission and UHV transmission projects,it is particularly important to ensure their safe operation.Therefore,transmission line status monitoring and online fault maintenance are of great significance.However,the provision of stable and reliable electrical energy is an important prerequisite for the normal operation of monitoring equipment.In the current multiple power supply methods,the current transformer power supply has good application value because of its small size,easy installation,and small environmental impact.But the conventional current transformer power supply method has the problems of unstable power extraction and low power extraction.In view of the above problems,this paper proposes an online energy acquisition method of double magnetic circuit based on adjustable impedence.In this method,a parallelr capacitor is connected to the secondary side of the open air gap coil to generate a parallel resonance between the capacitor and the coil’s excitation inductance,so that the impedance can be improved.the energy can be divided from the transmission line to the coil without air gap,through the branch of energy acquisition,so that the energy acquisition is greatly improved and the redundant electric energy is stored by the super capacitor.The supercapacitor can be discharged to supply power to the load when the branch of energy acquisition is insufficient.when the transmission line current is too high,the reverse current discharged through super capacity will input to the shunt capacitor of secondary side of the coil so that the main flux can be offseted and the core saturation can be avoided.By adjusting the magnitude of the reverse current,the current flowing into the branch of energy acquisition can be controlled continuously.In this thesis,the research on the energy acquision method is mainly about related control and circuit analysis of the branch of energy acquisition,rectification and voltage stabilization from the branch of energy acquisition to the load,bidirectional flow of electric energy between load and super capacitor,control method of impedance adjustment and the design of the current source,etc.Finally,this paper uses MATLAB Simulink simulation software to establish a simulation platform,and performs experiments on rectifier circuits based on PWM,bidirectional DC/DC circuits,conventional current transformer power supply,double magnetic circuit parallel resonance power supply and impedance adjustment method.The simulation results verify the feasibility and correctness of the theory in this thesis.The results show that the dual-magnetic-path parallel resonance energy acquisition method with adjustable impedance not only has a large electric power and a small starting current,but also can keep the energy extraction stable through the impedance adjustment method.Compared with conventional current transformers,it has great advantages.