金属网笼对雷击输电线辐射电磁场的屏蔽分析  

Shielding Behavior of Wire-mesh Cage to the Radiated Fields from Power Line

作　　者：李祥超[1,2] 陈则煌[1,2] 周中山[1,2] 陈璞阳 

机构地区：[1]南京信息工程大学中国气象局气溶胶-云-降水重点开放实验室,南京210044 [2]南京信息工程大学应用电磁学研究中心,南京210044

出　　处：《高压电器》2016年第2期50-56,共7页High Voltage Apparatus

基　　金：国家重点基础研究发展计划(973计划)(2014CB441405);国家自然科学基金项目(41075025)~~

摘　　要：针对金属网笼对雷击输电线辐射的电磁场的屏蔽性能的问题,通过对雷电回击过程的天线模型及金属网屏蔽效能的理论分析,利用雷电试验冲击平台(ICGS)模拟产生雷电注入输电线后辐射电磁波,进行金属网格屏蔽效能的实验。实验表明:对于433 MHz的模拟电磁信号,在模拟雷电流幅值小于17 k A时,金属网对雷电电磁信号的屏蔽效能为13 d B左右,此后屏蔽效能迅速下降,并于25 k A时降为0 d B;对于2.4 GHz的模拟雷电电磁信号,金属网笼对电磁波的屏蔽作用在雷电幅值达到22 k A之前,屏蔽效能维持在9 d B,随后迅速下降,并于27 k A时下降为0 d B;金属网笼的屏蔽效能不仅由外部电磁场的内向耦合决定还应考虑笼内部电磁场的多次折反射问题造成的电场、磁场值增强的问题。该研究对于使用金属网笼进行屏蔽具有一定的指导意义。The shielding behavior of bonded-junction wire mesh screens to the radiated fields from the power line is discussed at frequency of 433 MHz and 2.4 GHz respectively. Based on the antenna model of lightning return stroke and wire mesh screens theories, the impulse current generator system（ICGS）and a wire mesh screens are used to study plane-wave shielding effectiveness. For the 433 MHz electromagnetic wave,the screening effectiveness is13 d B when the lightning current amplitude is less than 17 k A and the effectiveness decreases with the increase of the lightning current amplitude. And it decreases to 0 d B at 25 k A. Similarly, the screening effectiveness to the2.4 GHz electromagnetic wave is 9 d B and decreases to be 0 d B when the lightning amplitude is 27 k A. This phenomenon is caused by the multi-reflection when the electromagnetic wave is strong enough. So the screening effectiveness of the wire mesh screens is dominated by electromagnetic inward coupling and the multi-reflection of the electromagnetic.

关 键 词：雷电 输电线 金属网笼 电磁屏蔽 屏蔽效能 

分 类 号：TM863[电气工程—高电压与绝缘技术]