I'm talking about power and not about voltage; the diameter of a conductor is mostly defined according to the current (hence, power) it will carry through (we'r

I'm talking about power and not about voltage; the diameter of a conductor is mostly defined according to the current (hence, power) it will carry through (we're talking about a 300 MW line, at peak time). You simply can't have conductors as large as trunks in the air.