Codes and standards for lightning often rely on simulations due to the difficult nature of lightning testing, as in the case of corrugated stainless steel tubing (CSST). A small set of simulations by CSST manufacturers were previously used to justify the suggestion that grounding CSST would make it safe from perforation in the presence of lightning. Such a small set of simulations does not account for the uncertainty of lightning and the situations where it may interact with CSST. We account for these uncertainties in this work by performing thousands of simulations that use different combinations of simulation parameters. For example, for one scenario we run 2560 simulations with a variety of different waveforms and different impedance values. The waveforms follow IEC 62305 with rise times ranging from 0.25 $$\upmu$$ μ s to 10 $$\upmu$$ μ s and fall times ranging from 100 $$\upmu$$ μ s to 1000 $$\upmu$$ μ s and the impedance values were varied by ± $$25\%$$ 25 % . Our results show that there are cases where grounding may prevent perforation, cases where grounding may reduce the damage but not prevent perforation and cases where grounding increases the chances of perforation. Our results further show that for lightning strikes with peak current greater than the median, there was never a case where grounding could have prevented perforation. Our methods provide a way to perform more comprehensive simulations to replicate what may happen in nature and better inform decisions made about codes and standards. In particular we show grounding of CSST will not prevent fires when assaulted by lightning with any reasonable degree of certainty.

中文翻译：

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评估波纹不锈钢管 (CSST) 接地安全性的闪电模拟变化

由于闪电测试的困难性，闪电的规范和标准通常依赖于模拟，例如波纹不锈钢管 (CSST)。CSST 制造商的一小组模拟以前被用来证明将 CSST 接地可以使其在雷电情况下不会穿孔的建议是合理的。这么小的模拟集并没有考虑闪电的不确定性以及它可能与 CSST 相互作用的情况。我们通过执行使用不同模拟参数组合的数千次模拟来解释这项工作中的这些不确定性。例如，对于一个场景，我们使用各种不同的波形和不同的阻抗值运行 2560 次模拟。波形符合 IEC 62305，上升时间范围为 0。25 $$\upmu$$ μ s 到 10 $$\upmu$$ μ s 和下降时间范围从 100 $$\upmu$$ μ s 到 1000 $$\upmu$$ μ s 并且阻抗值变化为± $$25\%$$ 25 % 。我们的结果表明，有些情况下接地可以防止穿孔，有些情况下接地可以减少损坏但不能防止穿孔，有些情况下接地会增加穿孔的机会。我们的结果进一步表明，对于峰值电流大于中值的雷击，从来没有接地可以防止穿孔的情况。我们的方法提供了一种执行更全面模拟的方法，以复制自然界中可能发生的情况，并更好地告知有关规范和标准的决策。特别是，我们表明 CSST 的接地在受到雷击时并不能以任何合理的确定性防止火灾。