The reason high-voltage lines can’t buried in the ground
Although it is steel and iron, the high-voltage wires are not as strong as you think. A super typhoon can scar the power grid.
Then why can’t all high-voltage wires be buried underground like urban underground cables, so that it can be done once and for all, and how many levels of typhoons are not afraid?
At present, there is no effective insulation material for UHV power transmission as the insulation layer of the wire. Therefore, UHV wires are exposed and cannot be buried in the ground.
There are distributed capacitors around the wires, and current can leak out through these capacitors, which increases consumption on the one hand; on the other hand, there is a danger of electric shock if any animal approaches.
Air is an insulator, but the earth is a conductor. In the air, you just need to put the wires directly there, but in the underground, you need to add layers of insulating shells outside the wires, otherwise the electricity in the wires will not go far, and there will be little leakage left.
Underground cables are more complicated in structure than overhead lines, have higher technical requirements, and are difficult to manufacture and construct. In addition, when cables are buried underground, it is not easy to find faults, and it is also difficult to repair and maintain.
Generally speaking, the cost of an underground cable with the same voltage level will be several or even dozens of times higher than that of a high-voltage line in the sky. No one wants the power to go out, but the power supply will not escape the ground. Once there is a failure, you have to “dig three feet” to check and repair the cables.
First, they have to go through the procedures for digging the “underground passage”; then, they have to work overtime to dig through the tunnel; then they have to check the underground cables section by section to find the fault point; finally, they can target the fault point and prescribe the right medicine. This is all the time of the big guys, and the power supply is also very wrong. They really want to resume the power soon.
To sum up, burying high-voltage lines in the ground poses both safety and economic problems.