摘要
Abstract
In order to protect sensitive equipments from harms of lightning electromagnetic impulse field and select suitable safeguard procedures,field intensity and distribution regularity of lightning return-stroke electromagnetic field under vertical discharge channel is required to be analyzed. Therefore,impulse function was used for expressing bottom current of the channel,meanwhile,combining modified transmission line exponential model and according to dipole technique,Maxwell e-quation set was worked out as well as analytical expressions of electric field and electromagnetic field of vertical channel in space were deduced. By means of Cooray-Rubinstein formula,horizontal electric field component under the condition of considering conductivity of the earth was worked out and computation expressions of horizontal electric field component, vertical electric field component and lateral electromagnetic field component of random field points around the channel were obtained. Furthermore,transformation laws of electromagnetic field of random field points around lightning channel with different horizontal distance,height and conductivity of the earth were studied. The results indicate that waveforms and am-plitudes of electric field and electromagnetic field are obviously affected by horizontal distance,height and conductivity of the earth which might provide reliable basis for selecting suitable safeguard procedures.关键词
雷电回击电磁场/垂直放电通道/偶极子法/脉冲函数/地表电磁场Key words
lightning return-stroke electromagnetic field/vertical discharge channel/dipole technique/impulse function/e-lectromagnetic field of the earth’s surface分类
信息技术与安全科学
