目前，超高压输电还找不到一种有效的绝缘材料做电线的外皮绝缘层，所以，超高压电线都是裸露的，是不能埋买在地下的。电线周围存在分布电容，电流可以通过这些电容漏出去，一方面增大消耗；另一方面，如果有任何动物靠近，也会有触电的危险。
At present, there is no effective insulating material for the outer insulation layer of UHV transmission lines. Therefore, UHV lines are bare and can not be buried underground. Distributed capacitors exist around the wires. Current can leak out through these capacitors, which on the one hand increases consumption, and on the other hand, if any animal is near, there will be the risk of electric shock.
空气是绝缘体，大地却是导体。在空中，只要把电线直接架在那里就可以了，但是在地下，要在电线外加上一层层的绝缘外壳，否则电线里的电没走多远，漏电就漏得所剩无几了。
Air is an insulator, but the earth is a conductor. In the air, as long as the wires are directly mounted there, but in the underground, we need to add a layer of insulation outside the wires. Otherwise, the electricity in the wires does not go far, and there will be little leakage left.