Influence of a lossy ground on lightning-induced voltages on overhead lines
Influence of a lossy ground on lightning-induced voltages on overhead lines
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DOI：
10.1109/15.536054
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发表时间：
1996-08
影响因子：
2.1
通讯作者：
F. Rachidi;C. Nucci;M. Ianoz;C. Mazzetti
中科院分区：
文献类型：
--
作者：
F. Rachidi;C. Nucci;M. Ianoz;C. Mazzetti
综合研究了有耗地面对雷击架空电力线感应电压的影响。地面电导率在雷电辐射场和线路参数的评估中发挥着重要作用。为了通过严格的理论计算，场和线常数都需要重要的计算时间，这对于感兴趣的问题来说仍然是令人望而却步的。本文的目的是讨论和分析各种简化的方法和技术，已提出的计算领域和线常数时，地面不能假设为一个完美的导电平面。关于辐射电磁场，它表明，水平电场，这是最受地面有限电导率的影响的分量，可以在一个准确的方式使用Cooray-Rubinstein简化公式计算。通过两个附加项：纵向接地阻抗和横向接地导纳，将不完全导电接地的存在包括在耦合方程中，这两个附加项都与频率有关。对于典型的架空线路，后者通常可以忽略不计，因为它对线路的总体横向导纳的贡献很小。关于接地阻抗，在文献中使用的几个简化的表达式之间的比较，并建立这些表达式的有效范围。它还表明，对于典型的架空线路的导线阻抗可以忽略不计，关于地面阻抗。
A comprehensive study on the effect of a lossy ground on the induced voltages on overhead power lines by a nearby lightning strike is presented. The ground conductivity plays a role in both the evaluation of the lightning radiated fields and of the line parameters. To be calculated by means of a rigorous theory, both fields and line constants need important computation time, which, for the problem of interest, is still prohibitive. The aim of this paper is to discuss and analyze the various simplified approaches and techniques that have been proposed for the calculation of the fields and the line constants when the ground cannot be assumed as a perfectly conducting plane. Regarding the radiated electromagnetic field, it is shown that the horizontal electric field, the component which is most affected by the ground finite conductivity, can be calculated in an accurate way using the Cooray-Rubinstein simplified formula. The presence of an imperfectly conducting ground is included in the coupling equations by means of two additional terms: the longitudinal ground impedance and the transverse ground admittance, which are both frequency-dependent. The latter can generally be neglected for typical overhead lines, due to its small contribution to the overall transverse admittance of the line. Regarding the ground impedance, a comparison between several simplified expressions used in the literature is presented and the validity limits of these expressions are established. It is also shown that for typical overhead lines the wire impedance can be neglected as regard to the ground impedance.