Почему нельзя закапывать высоковольтные кабели под землей?

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Что такое высоковольтный кабель?

Передача сверхвысокого напряжения подразумевает использование 500 Уровни напряжения кВ-1000 кВ для передачи электроэнергии.

Если 220 индекс передачи кВ 100%, относительные инвестиции на километр передачи сверхвысокого напряжения, относительная стоимость передачи электроэнергии за киловатт-час на сто километров и расход металлических материалов, и т.п., были значительно сокращены, и коэффициент использования линейного коридора был значительно улучшен.

В нашей повседневной жизни, мы часто можем видеть проект воздушной передачи сверхвысокого напряжения, думали ли мы над этим вопросом: почему не может быть похоже на городской подземный кабель, высоковольтные линии электропередачи все зарыты под землей?

The current underground cables are generally of lower voltage levels.

The transmission of lines with high voltage levels is often overhead, which is mainly a factor of cost and technology. 　　

Underground cables are more complex than the structure of overhead lines, with high technical requirements, производство, and construction difficulties, coupled with the cable buried underground, it is not easy to find faults, overhaul, and maintenance are also more difficult.

And in terms of cost, generally, the same voltage level of the underground cable costs 3 к 5 times higher than the overhead lines. 　　

Characteristics Of High-Voltage Transmission Lines

In particular, our common high-voltage level lines are typically used for long-distance transmission.

If underground cables are used, especially for long-distance transmission regularly through complex terrain, the costs and technical requirements can even skyrocket. 　　

С другой стороны, also the подземный кабель itself is inherently “hard”.

Overhead lines in the air in good thermal conditions, while the air around the underground cable does not flow, difficult to dissipate heat, which largely limits the level of power underground cables can transmit.

The important thing is that ultra-high voltage transmission has not been able to find an effective insulation material to do the outer skin insulation layer of the wire.

Следовательно, ultra-high voltage wires are bare and cannot be buried buy underground.

There are distributed capacitances around the wires, through which the current can leak out.

On the one hand to increase consumption, с другой стороны, if any animal is closed, there will also be the risk of electrocution.

Air is an insulation, but the earth is a conductor. In overhead lines, it is enough to put the wire directly there.

But in the underground, add a layer of insulation shell outside the wire, otherwise, the electricity in the wire did not go far, and the leakage of electricity will leak all that is left.

Underground cables are more complex than the structure of overhead lines, with high technical requirements, производство, and construction difficulties, coupled with the cable buried underground, not easy to find faults, overhaul, and maintenance are also more difficult.

Вообще говоря, the cost of underground cables of the same voltage level will be several times or even tens of times that of aerial high-voltage lines.

Ultra-high voltage cables buried underground have both safety and economic problems.

If a fault occurs, its inspection and repair of the cable is a very large project and cannot afford to toss and turn.

Следовательно, the current UHV cables should be hung high in the air.

Резюме

Underground cable conductors outsourced insulation and protective layer manufacturing are very strict, the human body’s normal contact with the outer skin of the cable will not have any danger.

Cable laying is also very careful, the cable is mostly buried in a special cable trench, cable row pipe, or cable tunnel, subject to good safety isolation and protection.

The depth is mostly less than half a meter, and the higher the voltage level, the deeper the cable is buried.

Более того, there will be a cable work well or a cable marker stake as a marker every few dozen meters on the ground where the cable is buried to remind people of safety.

Следовательно, underground cables mainly do not cause danger to residents.