This article investigates the effect of a simplified procedure, referred here as Rusck's approximation, which consists in obtaining the electrical potential at a given height by multiplying the vertical electric field computed at ground surface by the height considered, instead of integrating the vertical electric field from the ground surface up to the given height. This procedure is currently considered by several authors but, so far, has not been investigated in detail. The article shows that this approximation leads to significant deviations at close range from the strike but provides accurate results if the distance from the strike is higher than three times the height of the point considered. The article also shows that the distance between the line and the flash must be higher than three times the line height to obtain lightning induced voltage peak-values sufficiently high to produce line flashovers, as otherwise the flash will strike the line directly. As Rusck's approximation provides accurate results under such condition, it can be used for the assessment of indirect lightning performance of aerial power lines without any significant loss of accuracy.

中文翻译：

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Rusck近似对架空输电线间接雷电性能评估的影响

本文研究了简化过程的效果，此处称为Rusck近似，该过程包括通过将在地面上计算出的垂直电场乘以所考虑的高度来获得给定高度的电势，而不是对来自地面到给定高度。几位作者目前正在考虑使用此程序，但到目前为止，尚未进行详细调查。该文章表明，这种近似会导致在距打击点较近的距离处产生明显的偏差，但如果距打击点的距离大于所考虑点的高度的三倍，则可以提供准确的结果。该文章还显示，线与闪光灯之间的距离必须大于线高的三倍，以获得足够高的雷电感应电压峰值以产生线闪络，否则闪光灯将直接撞击线。由于Rusck的近似值在这种情况下可提供准确的结果，因此可用于评估架空电线的间接雷电性能，而不会造成任何重大的准确性损失。