摘要
为保护敏感设备免受雷电电磁脉冲场的危害并选择合适的防护措施,需分析垂直放电通道下雷电回击电磁场的场强及分布规律,为此,利用脉冲函数表示通道底部电流,结合回击电磁场的传输线回击电磁场的传输线(modified transmission line exponential model,MTLE)模型,根据偶极子法求解Maxwell方程组,推导垂直通道在空间产生电场与磁场的解析表达式,借助Cooray-Rubinstein公式计算在考虑大地电导率的情况下的水平电场分量,得出通道周围任意场点P(r,φ,z)的水平电场分量Er、垂直电场分量Ez与横向磁场分量Hφ的计算表达式,进而研究雷电通道周围任意场点在不同水平距离、高度以及大地电导率的电磁场变化规律。结果表明,电场与磁场的波形及其幅值受水平距离、高度和大地电导率的影响显著,为选择合适的防护措施提供了可靠的依据。
In order to protect sensitive equipments from harms of lightning electromagnetic impulse field and select SUltaole 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 equation 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.
出处
《广东电力》
2015年第6期113-119,共7页
Guangdong Electric Power
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
lightning return-stroke electromagnetic field
vertical discharge channel
dipole technique
impulse function
electromagnetic field of the earth＇s surface
