Research On Power Supply Of 110 KV And 220 KV On-line Monitoring Equipment Based On Wireless Power Transmission

The on-line monitoring of power systems is of great significance to ensure their stable operation.Particularly for on-line monitoring devices at 110 k V and 220 k V,there is often a significant voltage difference with ground,making direct power supply difficult.Presently,power supply methods such as battery,solar panel,and CT induction have been adopted.However,these methods suffer from problems such as insufficient supply stability,short lifespan,and low efficiency,which ultimately affect the stable operation of both the monitoring devices and the power system itself.Recently,the growing Wireless Power Transmission(WPT)technology has gained significant attention among researchers as a means of powering on-line monitoring devices.Firstly,this paper introduces a ’hollow transformer type’ wireless power transfer(WPT)topology.The theoretical model of the hollow transformer is utilized for the WPT system design,where the input AC voltage is 220 V at 500 k Hz,with a maximum input power of 30 W.The design parameter includes an output DC voltage of 5 V and an output power of 15 W,aiming at achieving constant voltage output with in-phase input and output voltage for complete compensation.The proposed WPT structures are designed for 110 k V and 220 k V power systems,respectively,and can achieve a transmission efficiency of more than 90%.Simulink is used to simulate the proposed topology,and the simulation results show that the WPT structure exhibits the characteristics of constant voltage output with matching phases of input and output voltage.The simulation-based transmission efficiency values are found consistent with the corresponding theoretical results,validating the theoretical derivations.Secondly,addressing the issue of power supply limitation that restricts a device to power an online monitoring device of only one voltage level,the proposed method involves utilizing a variable matching capacitance to enable multiple load supplies while maintaining a transmission efficiency of over 85%.To prevent excessive local field strength,this study incorporates anti-corona tape into the equipment and optimizes the coil structure by imitating the transformer layer winding,as well as encasing the coil with insulating paper to ensure a uniform electric field.Additionally,the use of a nested hollow insulator aims to prevent surface flashover.Thirdly,this paper presents the design of a 500 kHz inverter circuit and elaborates on its operational principles.The PLECS software is utilized to simulate and verify the design.Ultimately,the hardware and software components of the proposed power supply for the 110 k V online monitoring device are completed.The experiment confirms that the input and output voltages of WPT exhibit similar phase characteristics.The system achieves a transmission efficiency of 90.6%,with an error of approximately 5% in comparison to the theoretical value.An error analysis is conducted and proposed measures for improvement are presented.Lastly,the limitations of the equipment are summarized,and its future development is predicted.