which is the top most conductor in a transmission line?

Answer 1

Without looking at the pole, line, and insulator stack myself, I can't say for absolute certainty, but here is a general guide:

If you see a single wire high up in an urban residential area with only one small glass insulator (or none), it is the ground wire. If that wire has one large, or multiple insulators stacked together, then that wire is the high-voltage feed for the transformers for your house (anywhere from 2.5 kV to 15 kV depending on your power company).

In rural areas, if there is a single wire on a wood telephone pole, (and there is one large, or multiple insulators), it is a high-voltage feed.

On high-voltage 3-phase metal towers, the top conductors are usually the earth ground wires.

In general, look at the insulators... if there is only one, and the wire is smallish-diameter, then it is probably a ground wire. If there are multiple insulators, it is a high-voltage line.

Answer 2

Due to capacitance and induction, it is constantly changed. If you drive along a high voltage power line, periodlically you will see a tower that has a different arrangement of insulators and the lines coming into the tower swap around so that, perhaps, on the tower before they were 1-2-3 from top to bottom while on the tower after they are 2-1-3. The different arrangement (often a triangle if the other towers are vertical) allows the wires to swap locations without getting too close.

Answer 3

EARTH WIRE