due to the short discharge time and high energy of lightning, a strong electromagnetic field will be generated within a radius of 1-2km from the lightning strike point during the discharge process. According to the physics course in senior high school, metal objects in the alternating electromagnetic field will generate induced electromotive force (that is, the potential will increase), and if there is a ring-shaped metal object, it will generate induced current, and the potential formed by metal objects will vary according to its length, cross-sectional area, metal type, etc.
the solution is to make equipotential grounding for metal objects such as metal equipment and metal pipes in the dangerous goods yard, that is, under the influence of lightning strike, the potential of the metal objects in the whole yard increases and decreases at the same time, and there is no potential difference between the metal objects, thus avoiding the possibility of fire jumping.
Let me give you a typical case of lightning protection engineering: At 9: 55 am on August 12, 1989, No.5 storage tank of Huangdao Oil Depot in Qingdao Development Zone was struck by lightning, which caused a big explosion. Tens of thousands of tons of crude oil stored in the tank was detonated, and the flames soared to more than 1 meters. The blazing high temperature detonated No.1, No.2, No.3 and No.4 oil tanks one after another, and the whole Huangdao was caught in a sea of fire, and 2 people were buried in the sea of fire. There are many lightning protection towers in Huangdao oil depot, but the electrostatic grounding is not perfect. Its general design principle is to learn from the norms of the former Soviet Union. After analyzing the cause of the accident, the lightning protection experts supplemented the Lightning Protection Code, and its measures to prevent lightning electromagnetic pulse have been implemented so far.