雷击下输电线路上行先导稳定起始的初始流注区域空间电荷判据

Space Charge Criterion of the Initial Streamer for the Stable Inception of Positive Upward Leader Under Lightning Strikes

雷电作用下准确判断线路上行先导的稳定起始时刻显著影响线路雷电屏蔽性能分析的准确性,而如何确定合理的判据是研究重点。该文依据导线正极性上行先导发展数值模型,通过计算不同条件下的导线上行先导发展过程,提出正极性上行先导的初始流注区域临界空间电荷判据。研究表明,导线出现稳定的上行先导时,初始流注区域的空间电荷量存在一临界值,该临界值仅受导线半径的影响,与导线高度、运行电压及雷电参数无关。与已有的上行先导起始判据相比,以此临界值作为稳定起始时刻判据可以更好地解释空间电荷对上行先导的屏蔽作用随导线半径增大而减弱的现象,并进一步探讨该判据与海拔高度的关系,可为输电线路雷电屏蔽性能的分析提供参考。

The accurate judgment of the stable inception moment of the upward leader under the lightning strike affects the accuracy of the lightning shielding analysis of the transmission line.Therefore,how to establish reasonable criteria is crucial.In this paper,based on the numerical model of positive upward leader incepted from the conductor,and by analyzing the growth process of the leader incepted from the conductor under different conditions,a critical space charge criterion for the stable upward leader inception is proposed.Research shows that there is a critical space charge quantity of the initial streamer region when the stable upward leader incepts.The critical value is only affected by the radius of the wire and is independent of the conductor height,operating voltage,and lightning parameters,which can be served as the criterion of the stable inception moment of the upward leader.Compared with the available criterion of the upward leader,the proposed criterion can better explain that the shielding effect of space charge on the upward leader decreases with the increase of wire radius.The relationship between the criterion and altitude is also discussed in this paper.Thus,the proposed method provides a theoretical basis for the analysis of the lightning shielding performance of transmission lines.