Practical caution on lightning protection of grounded large structures against lightning parameters for height of evaluation positions along grounded large structures

摘要

The "deformation on waveforms in conductive currents of lightning return strokes to the earth I-c. for height on evaluation positions along the grounded large structures struck by the lightning return strokes" is mathematically comprehended in approximation with the fundamental explanation on ''transfer theory between conductive currents I_c and displacement currents I_d on surfaces of high voltage conductive objects", "electric fields along surfaces of high voltage large conductive objects E as determinant factors on transfer between conductive currents I_c and displacement currents I_d along high voltage large conductive objects" and "propagation on conductive currents I_c and potential ψ". The conventional experimental result, which has been already measured, on the characteristics in the deformation in the wave fronts in the conductive currents of lightning return strokes to the earth with tails I_c for the height in the evaluation positions along the high rise towers struck by the lightning return strokes is shown to be mathematically comprehended broadly. Lightning parameters on lightning protection of the grounded large structures are varying by the height of the evaluation positions along the grounded large structures owing to "deformation on waveforms in conductive currents of lightning return strokes to the earth I_c for height on evaluation positions along the grounded large structures struck by the lightning return strokes". The practical caution on the lightning protection of the grounded large structures against the lightning parameters for the height of the evaluation positions along the grounded large structures is insisted. In the lightning protection of the grounded large structures, the varying on the lightning parameter for the height of the evaluation positions along the grounded large structures must be carefully treated. 1. The deformation on the wave fronts in the conductive currents of the lightning return strokes to the earth with the tails I_c for the height on the evaluation positions along the grounded large structures with large width or large depth, which aren't so high, struck by the lightning return strokes is able to be predI_cted to be drastically appeared as well as the deformation in the wave fronts in the conductive currents of the lightning return strokes to the earth with the tails I_c for the height in the evaluation positions along the high rise towers struck by the lightning return strokes on the conventional experimental result. In short, the "enough high potential ψ along surfaces on the grounded large structures with large width or large depth which aren't so high" and "enough large surfaces on the grounded large structures with large width or large depth which aren't so high" cause the strong capacitive coupling between the grounded large structures and the grounded large surroundings of the grounded large structures including the ground to bring about the deformation on the wave fronts in the conductive currents of the lightning return strokes to the earth with the tails for the height of the evaluation positions along the grounded large structures I_c. 2. When tops of large size modern buildings including the high rise towers are struck by lightning return strokes to the earth 10/350 μs, 1/200 μs and 0.25/100 μs for examples, the average steepness on the rises in the conductive currents of the lightning return strokes for lower evaluation positions along the large size modern buildings I_c is deformed to be exactly larger. The high voltage, based on self-inductance and mutual-inductance, induced by the neighboring magnetic fields B from the deformed conductive currents of the lightning return strokes to the earth I_c is exactly higher than the high voltage induced by the neighboring magnetic fields B from the badly assumed conductive currents of the lightning return strokes to the earth 10/350 μs, 1/200 μs and 0.25/100 us on the lower evaluation positions along the large size mo