土壤电导率分层对地闪回击水平电场时空分布规律的影响  

Influence of Soil Conductivity Stratification on Temporal and Spatial Distribution of Ground Flashover Return Strike Horizontal Electric Field

作　　者：毕睿华[1] 

机构地区：[1]南京工程学院,南京211167

出　　处：《电瓷避雷器》2017年第6期121-126,共6页Insulators and Surge Arresters

摘　　要：地闪回击产生的水平电场是架空输电线路产生雷电感应过电压的主要原因,目前国内很多学者对电磁场时间变化规律进行了分析,但是针对电磁场空间分布特征还没有过多的研究。采用了二维时域有限差分法(2D FDTD),研究土壤电导率水平分层情况下地闪回击水平电场时空分布特征。结果表明:1)在均匀有耗大地情况下,水平电场分布从回击通道开始以光的传播速度沿近似半球面向远处传播时,随着时间的增加,水平电场的分布也相应增加。在近地面处,水平电场极性与周围其他空间处的水平电场相反,且随着传播距离的增大,该区域范围也在扩大。相比于均匀有耗大地的情况,理想大地情况下水平电场传播显得比较简单;2)土壤分层情况下的水平电场也出现了水平电场极性反转的现象。当上层土壤电导率大于下层时(Case1),其极性反转区域随传播距离整个极性反转区域形状呈现出上升沿较陡、下降沿较缓的特征。The horizontal electric field generated by lightning is the main reason for the overhead transmission line from lightning induced overvohage, many domestic scholars on the variation of electro- magnetic field time are analyzed, but according to the electromagnetic field distribution characteristics of space is not too much research. In this paper, the two-dimensional finite difference time domain （2D） method is used to study the temporal and spatial distribution characteristics of the horizontal electric field of the lightning return stroke in the case of soil electrical conductivity stratification （FDTD）. The results show that： 1） in the homogeneous earth under the condition of horizontal electric field distribution from the back channel begins with the speed of light propagation along the propagation distance for approximate hemisphere, as time increases, the distribution of the horizontal electric field is also increased. In the near surface, the horizontal electric field polarity is opposite to the horizontal electric field in the other space, and with the increase of the propagation distance, the range of the region is also expanding. Com- pared with the case where the earth is uniform, the propagation of horizontal electric field in the ideal ground is relatively simple; 2） the horizontal electric field is reversed in the horizontal electric field under the condition of layered soil. When the conductivity of the upper soil layer is greater than that of the lower layer, the polarity reversal of the horizontal electric field is obviously less than that of the upper layer.

关 键 词：水平电场 有限电导率 水平分层 二维时域有限差分 空间分布 

分 类 号：TM863[电气工程—高电压与绝缘技术]