[Animats]

Radar power needed increases as the fourth power of the range.

The state of the art in radar is that sensing power lines and similar wires is not reliable. 77GHz radars employed in cars can sense people and bicycles, but that's not good enough. There's been much effort put into power line detection for aircraft (helicopters hit power lines about 50 times a year in the US) but no good solution yet. Drones zipping around streets with overhead wires and trees is not yet workable.

[genericuser]

It seems like power lines would be able to be detected with system measuring changes in magnetic fields, perhaps based off current induction sensors. However clearly a system like that does not yet exist and that would not help with other obstacles. And I agree with your statement that this is currently not workable.