建筑物尺度对避雷针防雷性能影响的数值评估

Numerical evaluation of effects of building scale on lightning rod protection performance

为研究闪电先导与地面建筑物的相互作用,根据长间隙放电的物理过程建立了包含上行迎面正先导的三维负极性先导发展模型。利用模拟电荷法计算了电晕区的电位分布及电晕电荷量,作为上行正先导是否满足激发起始的判断条件,建立了上行正先导的起始传播模型,利用该模型评估了建筑物形状特征对于闪击距离的影响。研究表明:随着回击电流峰值、建筑物垂直高度或避雷针高度的增大,闪击距离也逐步增大;在建筑物垂直高度不变的条件下,随着避雷针高度的增加,闪击距离逐步增大,当避雷针高度大于30m后,闪击距离的变化不再明显。

In order to study the interaction of lightning leaders and structures, an inception model of upward leader based on the mechanism of the long air gap discharge process was proposed, and a three-dimensional physical model of downward leader with upward leader developed. The total charge and charge distribution in down leader were studied by employing the charge simulation method. The corona charge was used as judgment condition of the initial development. The influences of the features of building, such as the horizontal scale of the building and the height of the building, on the strike distance were evaluated by the proposed model. The major results are as follows： （1） The stroke distance increases gradually as the peak of the return stroke current, vertical height of the building or the height of the lightning rod increases. （2） When the vertical height of the building assumes to be constant, the overall trend of strike distance increases gradually as the lightning rod height increases. The changes of the strike distance are not obvious as the height of the lightning rod is more than 30 m.