预测竖直杆体的年雷击率

介绍了一种预测竖直杆体年雷击率的有效方法.该方法首先根据上行先导对下行先导的拦截条件推出竖直杆体的引雷空间边界方程,在这一引雷空间域内按雷击距作出杆体的受雷曲面,再从雷电流的概率分布出发给出雷击距累积概率密度函数的一般表达式.杆体的等值暴露面积是通过在受雷曲面上进行空间积分运算来获得的,其中下行先导定向取向角的随机性也被加以考虑,最后由雷击距累积概率密度函数和等值暴露面积来计算杆体的年雷击率.为了校验该方法的可行性,文中还将计算结果与实测结果进行了比较,比较表明,两者能基本取得一致.

Prediction of the Annual Incidence of Lightning Strikes to Erect Masts

An efficient procedure is proposed for predicting the annual incidence of lightning strike to erect masts. In the proposed procedure, the border equation of attractive volume of an erect mast is derived from the interception condition of upward leader to downward leader. The collection surface of the mast is positioned inside the attractive volume in terms of the lightning striking distance. A general expression is also given for the probability density function of lightning strike distance based on the probability distribution of lightning current. With the randomness of downward leader strike angle taken into account, a spatial integration is performed on the collection surface to evaluate the equivalent exposure area of the mast. Then, the annual number of lightning strike to the mast is obtained from the equivalent exposure area and the probability density function of lightning strike distance. In order to confirm the validity of the proposed procedure, a comparison is made between calculated and observed results. A better agreement is shown between them.