Study On The Structure And Receiving Characteristics Of Magnetic Loop Antenna For Lightning Direction Finding

Lightning is a kind of frequent natural weather,which is often accompanied by high voltage,high current and strong electromagnetic pulse radiation,which poses a great threat to human life and property.Lightning disaster is a very serious natural disaster,and it can effectively reduce the loss caused by lightning disaster by giving early warning and locating the lightning power quickly.Therefore,the research of lightning location detection technology has practical significance.In this paper,the Magnetic Loop Antenna(MLA)in lightning location system is studied deeply and proposes a method to determine the coil parameters when the receiving efficiency of MLA is optimal,the theoretical basis for the optimal design parameters of the MLA is provided and the structure of the traditional OMLA is improved.The experimental data show that the improved MLA can improve the angle measurement accuracy by about 39%.The structure distribution of the research content is as follows:(1)Introduces the research background and purpose of MLA detection technology,briefly reviews the research history and current situation of MLA detection accuracy in recent decades at home and abroad,and makes a detailed introduction to the structure research of MLA.(2)Introduces two detection methods of OMLA,Magnetic Direction Finding(MDF)and Combined Positioning Method(CPM),and describes the positioning principle,advantages and disadvantages of the two methods,as well as application scenarios.Furthermore,it is pointed out that the main causes of the positioning errors of the OMLA are polarization error,terrain error and antenna structure error.The causes of each error and the current solutions are analyzed.Finally,the transmission path loss and antenna loss are analyzed when the electromagnetic signal is transmitted and received,which will affect the receiving characteristics of the MLA.(3)In this paper,the receiving characteristics of Low-Frequency Electromagnetic Pulse(LF-EMP)of OMLA are studied,aiming at the low-frequency electromagnetic pulse signal whose main frequency covers 10khz-400khz and proposes a method to determine the coil parameters of the MLA in the best receiving efficiency.In this method,the frequency scaling coefficient?,skin effect loss coefficient K_j and proximity effect coefficient K_x are introduced for research and calculation.The experimental results show that the method can determine that the receiving efficiency?of the MLA with radius of 10cm,15cm and 20cm reaches the maximum when the number of turns is about 60,70 and 80,and the corresponding?is 0.127,0.501 and 0.920 at the frequency of 10kHz.Compared with the existing research in this field,this method can further determine the coil turns of different parameters of the MLA to achieve the best benefit through the receiving benefit?of the MLA.(4)The traditional OMLA may have some problems such as incomplete orthogonality and plane distortion,a novel Three-Loop Magnetic Loop Antenna(TLMLA)structure is proposed.The antenna uses three magnetic loops to receive the electromagnetic signals radiated by the same mine power supply,which avoids the limitation that the OMLA can only use two loops to obtain the azimuth angle of the mine power supply.The mutual inductance coefficient M is introduced to calculate the mutual inductance electromotive force between each magnetic loop,and then the actual induced electromotive force received by the MLA is calculated,and finally the azimuth angle?is calculated.Comparing the calculated data with the angle measurement error of traditional OMLA,it can be concluded that the angle measurement error of TLMLA is generally less than that of OMLA in the range of electromagnetic pulse signal angle from 0�to 360�.The angle measurement error of TLMLA is reduced by 39%compared with that of OMLA.