Because the design of high-voltage towers is relatively high, and some of them are still on the mountains, lightning strikes are inevitable in rainy weather. If lightning strikes the transmission line, it will affect the voltage of the whole line system or cause irreversible damage to the transmission line and connected equipment. Therefore, in order to protect the line from being struck by lightning, it is necessary to design a special line to accept lightning strikes and make it attract lightning.
Lightning rods are usually in direct contact with towers or the earth through special structures. Each tower has a corresponding lightning rod grounding device. When lightning strikes the lightning conductor, lightning current is introduced into the earth through the tower and grounding device, thus protecting the safety of the line.
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Precautions:
1. Generally speaking, the deeper the foundation is stressed, the smaller the volume is. However, due to the influence of groundwater, the probability of silt and quicksand will increase after the foundation is deeply buried, which will bring great difficulties to the construction, not only affecting the construction period, but also increasing the investment.
2. Due to the particularity of geology and the limitation of buried depth, it is safer and more economical to adopt shallow buried foundation at present, and the uplift stability can be met by appropriately increasing the size of foundation slab and increasing the self-weight of foundation.
3. The buried depth of linear tower is controlled at about 2m, and the buried depth of load-bearing tower is controlled at about 3 ~ 4m, which can reduce the influence of groundwater on construction. At the same time, according to the actual geological conditions of the project, the stress of each foundation tower is optimized one by one, especially for the load-bearing tower which has great influence on the cost. The way of two pulls and two presses or three pulls and one press is economical and reasonable.
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