Power lines also radiate em waves:
And the radiation should cause some energy loss.
How can we deduce logically whether the radiation loss for 50/60Hz power transmission lines are negligible? I know in low frequencies the loss is less but in this case the lines can be too long upto 2km. Is there a way to simplfy this and formulate the radiation loss roughly? Should we start modelling it like a 60Hz 2km dipole antenna?
Best Answer
There are many kinds of power loss associated with power transmission lines:
Resistive - due to the current in the wires heating them up, and also induced currents in nearby conductors.
Leakage - current flowing in places that it shouldn't, such as contaminated insulators, corona discharge, etc.
Radiation - electromagnetic waves carrying energy away from the wires.
The last one is the one you're asking about, and it is by far the least significant of the three.
No, you can't treat the wire as a "dipole". You have to treat it as an actual transmission line, because the spacing among the conductors and between the conductors and ground is very much less than a wavelength. This is what limits the ability to couple electromagnetic energy to "free space" — the electrical and magnetic fields are almost entirely canceled out right at the source.