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The importance of lightning protection for transmission lines

Lightning is a magnificent and somewhat intimidating electrical discharge accompanied by lightning and thunder. The condition of lightning is that there is accumulation and polarity in the thunderstorm cloud. Thunderbolts generally occur in cumulonimbus clouds with strong convection development, so they are often accompanied by strong gusts and storms, sometimes accompanied by hail and tornado, and often ice crystals in the upper part of the cloud. The freezing of ice crystals, the breaking of water droplets, and the convection of air create electric charges in the clouds. The distribution of charge in the cloud is complex, but generally speaking, the upper part of the cloud is dominated by positive charge and the lower part by negative charge. Thus, there is a potential difference between the upper and lower parts of the cloud. When the potential difference reaches a certain degree, it will produce a discharge, which is a common lightning phenomenon. Lightning has an average current of 30,000 amperes and a maximum current of 300,000 amperes. Lightning has a very high voltage, about 100 million to 1 billion volts. When the charged thunder clouds get close to a bump on the ground, there is a violent discharge between them. In the discharge process, due to the sudden increase of temperature in the flash, the volume of air expands sharply, resulting in a shock wave, resulting in strong thunder. At the point of lightning discharge, there will be a strong flash of light and the roar of an explosion.