山区典型地形雷击地闪密度分布差异研究

地闪密度是各项防雷设计的基础参数,研究一定范围山区内不同地形地闪密度分布的差异可以获取更准确的山区地闪密度分布图。文中首先定义了表征山区不同地形落雷密集程度的落雷分布系数这一概念,利用电气几何模型(EGM)中的击距理论推导了山顶、山谷、山脚地区的落雷分布系数理论计算公式。然后对比了山区典型地形落雷分布系数理论计算公式的差异,研究了不同因素对山区典型地形落雷分布系数的影响。最后利用某省不同地区10年的雷电定位系统数据做了实例验证。研究结果表明:山顶地区地闪密度大于山谷、山脚地区地闪密度;山体坡度越大不同地区的地闪密度差异越明显;50%雷电流幅值越大的地区地闪密度差异越明显;地形宽度变大地闪密度差异逐渐减小并趋于稳定。

Study on Distribution Difference of Lightning Ground Flash Density in Typical Mountainous Terrain

The ground flash density is the basic parameter of various lightning protection design,studying the differ?ence of ground flash density in different terrains within a certain range of mountains can obtain more accurate light?ning density maps in mountainous areas.In this paper,the concept of lightning distribution coefficient which charac?terizing the density of landmines in different mountainous terrain is defined.The theoretical calculation formula of the lightning distribution coefficient in the mountain top,valley and foothill is deduced by using striking distance the?ory of the electrical geometric model(EGM).The difference of lightning distribution coefficients in the typical moun?tainous terrain is compared.The influence of different factors on the lightning distribution coefficient of typical moun?tainous terrain is studied,and use a province’s 10years lightning positioning system data as an example to verify.The results show that the ground flash density of mountain top area is greater than it of the valley and foothills.The greater the slope of the mountain,the more obvious the difference in ground flash density in different regions.The dif?ference in ground flash density is greater in regions with bigger 50%lightning current amplitudes.The difference in ground flash density with increasing terrain width gradually decreases and tends to be stable.