雷电梯级先导通道电流模型

Model of stepped leader current for simulation of lightning

雷电梯级先导通道电流模型是雷电运动仿真和雷击研究的基础,在防雷工程、雷电绕击输电线路的理论研究中必不可少.建立了梯级先导的物理模型,该模型由主通道和先导头部区域两部分组成;给出了雷电梯级先导通道电流的数学模型,该模型较精确地描述了雷电向地面发展的梯级性和先导头部电荷聚集特性;采用模拟电荷法和偶极子法求解了雷电梯级先导产生的地面电场,仿真结果表明,远区地面电场的平均峰值、峰峰时间间隔与雷电观测值,以及不同回击电流峰值下的近区地面电场与人工引雷观测结果均具有较好的一致性.

Model of stepped leader current is the basis of lightning movement simulation and strike analysis, and it is indispensable for lightning protection design, theoretical research of shielding failure for transmission lines, etc.. Physical model of stepped leader was given, which includes a main channel and a tip. Cur- rent model of stepped leader was also given, which well simulates the stepwise propagation of lightening and charge change properties of stepped leader＇s tip. Electric field on the ground level produced by stepped leader was derived and calculated by charge simulation method and dipole technique, and its simulation results show that the average electric field peaks and time interval between stepped leader pulses of far-zone field agree well with the measured data. The close fields under different return strike current peaks also agree with the measurements of triggered-lightning.