Why are ultra-high voltage cables hanging in the sky

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Author：Henan Shenghua Click： Time：2019-11-14 00:00:00

In daily life, we can often see high-voltage cable racks in mid air in suburban fields. Have you ever considered why high-voltage cables need to be set up like this and buried underground? Isn't it better?

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Actually, many people may not have noticed that cables buried underground generally have lower voltage levels, while those with higher voltage levels choose overhead methods. The reason for this difference is due to cost and technical reasons.

Underground cable laying is much more complex than overhead cable, with higher technical requirements and more difficult construction. For the same voltage level, choosing underground cable is 3 to 5 times more expensive than choosing overhead cable.

High voltage cables, on the other hand, are usually used for long-distance transmission and often cross rivers and mountains. If underground cables are used, both in terms of technology and cost, they will definitely go up in a straight line.

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And there is also a very important point, there is no effective insulation material for ultra-high voltage transmission, so ultra-high voltage wires are exposed. Therefore, burying such cables underground poses a safety hazard and is not feasible. Choosing overhead can effectively solve this problem, as air is the best insulator.

The insulation and protection layers of common underground cables in the city have very strict requirements, and there is no risk of life in normal direct contact with the human body

Moreover, the laying of cables is also very particular. There are usually dedicated cable trenches for burying cables, as well as tunnels or pipelines for burying cables. The depth is generally required to be less than half a meter, depending on the voltage level of the cable. Generally, the higher the voltage, the deeper the cable is buried. If buried too shallow, there may be a risk of environmental impact or lightning strikes. We often see signs of cable piles on the ground, so underground cables will not have a significant impact on human life and safety.

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Why are ultra-high voltage cables hanging in the sky

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