雷击金属管管内线缆耦合特性分析  

Coupling Characteristics of Lightning Strike Cable Inside Metal Tube

作　　者：李祥超[1] 文巧莉 李诗怡 欧阳文 储蕾 LI Xiangchao;WEN Qiaoli;LI Shiyi;OUYANG Wen;CHU Lei(Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science&Technology,Nanjing 210044,China)

机构地区：[1]南京信息工程大学气象灾害预报预警与评估协同创新中心,南京210044

出　　处：《电瓷避雷器》2022年第5期1-8,18,共9页Insulators and Surge Arresters

基　　金：国家重点研发计划(编号:2017YFC1501505)。

摘　　要：针对雷击金属管,金属管内部线缆耦合雷电电磁脉冲的问题,通过对电场理论及同轴耦合理论的分析,利用理论和试验相结合的方法,采用8/20μs波形雷电流注入3种不同半径的金属管,进行冲击耦合试验。试验结果表明:金属管内部同轴线缆耦合的电压峰值与能量随冲击电流的增大而增大;当管内线缆终端开路,耦合电压随金属管半径的增大而增大,终端屏蔽层接地与终端接50Ω的匹配电阻时,耦合电压随金属管半径的增大而减小。通过频谱分析可得:金属管内部同轴线缆终端开路以及终端接50Ω匹配电阻时,都是150 kHz~300 kHz时频谱振幅最强;屏蔽层接地时,1 MHz频段振幅最强,高频分量丰富,这可能是因为芯线中产生了高次谐波。利用实验数据拟合曲线,反推出当雷电流达到35 kA,金属管长度为30 m时,终端耦合电压约为158 V。这对后端设备做雷电防护设计具有一定的参考价值。Aiming at the problem of lightning strikes against metal tube, the cables inside the metal tube are coupled with lightning electromagnetic pulses, through the analysis of electric field theory and coaxial coupling theory, using the method of combining theory and experiment, using 8/20 μs waveform lightning current to inject three metal tube with different radii to conduct impact coupling test. The test results show that the coupling voltage and energy of the coaxial cable inside the metal tube increase with the increase of the impulse current. When the cable terminal in the tube is open, the coupling voltage increases with the increase of the radius of the metal tube. When the terminal shielding layer is grounded and the terminal is connected with a matching resistance of 50 Ω, the coupling voltage decreases with the increase of the metal tube radius. Through spectrum analysis, it can be obtained: when the coaxial cable inside the metal tube is open and the terminal is connected with a 50 Ω matching resistance, the spectrum amplitude is the strongest at 150 kHz ~300 kHz.When the shielding layer is grounded, the 1 MHz band has the strongest amplitude and rich high-frequency components. This may be due to higher harmonics generated in the core wire. Using the experimental data to fit the curve, it is deduced that when the lightning current reaches 35 kA and the length of the metal tube is 30 m, the terminal coupling voltage is about 158 V. This has certain reference value for the lightning protection design of back-end equipment.

关 键 词：金属管 雷电流 同轴线缆 耦合电压 

分 类 号：TM863[电气工程—高电压与绝缘技术]