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Abstract Since ancient times, lightning disasters have undoubtedly been an unstoppable threat to humanity. During thunderstorms, lightning often damages objects on the ground, such as buildings and structures. Since Franklin invented the lightning rod in 1752, lightning rods have been used worldwide to prevent direct lightning strikes in various fields such as high-voltage power transmission lines, outdoor chemical sites, highways, land and sea wind farms, and forest lightning fire protection. It has been proven that lightning accidents still occur frequently in places where lightning rods are installed and the protective angle method is used. In order to further study the protective effect of lightning rods and identify the shortcomings of lightning rod protection , negative lightning strikes are taken as the research object, to analyze the limitations of lightning rods in preventing direct lightning strikes from the working principle of lightning rods.
Key words Lightning rod; Direct lightning strike; Protective angle method; Limitation
(ProQuest: ... denotes formulae omitted.)
At present, lightning rods are the main protective measures against direct lightning strikes worldwide, but lightning accidents continue to occur. In June 2008, a major fire accident occurred due to a lightning strike at Maoming Petrochemical; on July 23, 2011, a lightning strike caused a major accident in Wenzhou highspeed train collision. According to the statistics, China's power grid suffers more than 350 000 lightning strikes every year, with faults accounting for 47. 6% of the total. The continuous occurrence of lightning accidents indicates that the current protection methods using lightning rods and protective angle methods cannot effectively achieve lightning protection goals. Therefore, it is very important to study the limitations of lightning rods and protective angle methods.
1 Lightning rod and its working principle
1.1 Lightning rod For the prevention method of direct lightning strikes, the lightning rod invented by Franklin is currently mainly used globally as the core technology. The lightning rod is composed of a section of conductive metal material with a needle like end[1].
1.2 Working principle of lightning rod In 1752, Franklin first proposed that " lightning rods will release the charge of thunderstorms to prevent the occurrence of lightning". But it was found that this was not the case in practical applications. After installing lightning rods in the powder warehouse...