noun
power line; transmission line
Refers to high-voltage cables and wires used to transmit electricity over long distances, typically seen on pylons or towers.
山の上に新しい送電線が建設された。
A new power line was constructed on the mountain.
送電線の下には家を
It's better not to build a house under a power line.
電線 is a general term for any electric wire or cable, whereas 送電線 specifically denotes power transmission lines.
Compound of 送電 (sōden, 'power transmission') + 線 (sen, 'line, wire').