雷电脉冲电磁场对电站敏感设备的电磁干扰  

Electromagnetic Interference of Lightning Pulse Electromagnetic Field to Sensitive Equipment in Power Stations

作　　者：张晓[1] 余占清[1] 罗兵 王绍安[1] 蔡汉生 黄莹 

机构地区：[1]清华大学电机工程与应用电子技术系电力系统及发电设备控制和仿真国家重点实验室,北京100084 [2]南方电网科学研究院有限责任公司,广州510080

出　　处：《高电压技术》2014年第6期1696-1702,共7页High Voltage Engineering

基　　金：国家自然科学基金(50907036);国家重点基础研究发展计划(973计划)(2011CB209403);特高压工程技术(昆明;广州)国家工程实验室开放基金(编号略)~~

摘　　要：为研究雷电脉冲电磁场对电站敏感设备的干扰情况,研究了雷击大地时近场和远场区脉冲电磁场特性,对比分析了不同回击模型的计算结果;提取雷电脉冲电磁场中的有效干扰分量,与标准规定的电磁兼容阈值进行比较。考虑到设备外壳及墙体的屏蔽效能,结合广东地区雷电活动统计规律,分析了不同距离和通道电流下发生雷击地面时的电磁干扰情况以及发生故障的概率。结果表明,在20 dB屏蔽效能下,距离敏感设备中心300 m外区域发生雷击时,雷电流幅值>150 kA时才可能导致设备外壳端口的电磁干扰超标;考虑距离电站200 km范围内的所有雷电情况,20 dB屏蔽效能下站内敏感设备发生雷电电磁干扰的总电磁干扰超标概率为0.006次/a;40 dB屏蔽效能下的超标概率为2.2×10-5次/a。In order to evaluate the interference of lightning electromagnetic impulse（LEMP） on electromagnetic-sensitive equipment, we investigated the characteristics of the pulsed electromagnetic fields in both nearby and faraway areas when lightning striked the earth. The calculated results of different return-stroke models were compared and analyzed. Then we extracted the effective jamming component of LEMP and compared it with the regulated electromagnetic compatibility threshold. Considering the shielding effectiveness of equipment shell and wall, as well as the statistics data of the lightning activities in Guangdong Province, China, we analyzed the electromagnetic interference（EMI） and failure probability when lightning of various channel currents strikes the earth at different distances. The results show that, when the shielding effectiveness is 20 dB and the lightning strike occurs farther than 300 m away from the center of sensitive equipment, the lightning current has to be larger than 150 kA to cause excessive EMI. Taking into account the lightning strikes in a scope up to 200 km distance from a power station, we calculated the total over-standard rate of EMI to sensitive equipment in the station, which is 0.006 and 2.2×10-5 times per year for the cases of 20 dB and 40 dB shielding effectiveness, respectively.

关 键 词：雷电 脉冲电磁场 回击模型 电磁干扰 电磁兼容 概率 

分 类 号：TM937.3[电气工程—电力电子与电力传动]