Mechanism Analysis and Multiphysics Validation of Lightning Attenuation in Constrained Space

Abstract

The problem of resistance reduction has always been the key and difficult point of lightning protection. However, the problem of reducing the grounding resistance efficiently has not been solved. A method is introduced in this paper to solve this problem from the lightning current attenuation. The lightning discharge shock wave mechanism, shock overpressure reflection mechanism, and arc truncation mechanism are included to theoretically analyze the lightning current attenuation mechanism. The overpressure of the lightning discharge is much higher than the cut-off arc radial tolerance pressure, which contributes to the temporarily closing of discharge channel. Moreover, a lightning discharge model is established in COMSOL to simulate the process of discharge in lightning current. The results show that the pressure in the tube reaches up to $4\times 10$ 8 Pa rapidly, and the velocity in the mouth of the tube could reach as high as 4200 m/s. Finally, the current attenuation experiments are designed to validate the lightning current attenuation effect. The results show that the current is attenuated by the action of the prototype, the amplitude of the impulse current decreased from 66.95 kA to 35.10 kA, and the steepness of the impulse current decreased from 18.49 kA/ $\mu \text{s}$ to 4.14 kA/ $\mu \text{s}$ . All of the results show that this method could efficiently attenuate lightning currents.

Keywords

• Grounding resistance
• lightning current
• lightning protection
• current attenuation