Doubts on Skin effect & Electricity

[cool0crash]

Hi all! This is my first post :D

I came across skin effect which blocks propagation of an em-wave within a conductor...
But doesn't the energy generated at an electric plant reach our house through conductors flowing for over a 1000 miles sometimes?

If I have to consider it just as an alternating voltage/electric field which makes the charge carriers to flow such long distance, then I have these 2 doubts:
1. Can just 11000 volts be sufficient for pulling / pushing electrons in the conductor after thousands of miles from the source?
2. Even though it is an alternating electric field at the source, while propogation, there will an alternating magnetic field around the conductor which makes it an em wave. And now the same skin effect should work here to to limit the propagation to just a few millimeters or cms...

Thanks in Advance for whoever clears my doubts :P

 

[Bob S]

The interstate power line voltage in the U.S. is often over 700,000 volts. See
http://en.wikipedia.org/wiki/Overhead_power_line
Higher voltage reduces the current. The power line conductor diameter is small relative to the skin depth at 60 (or 50) Hz, so the skin loss is small. The actual power is carried in an em wave between the power line conductors (the Poynting vector), because the energy flow (magnitude and direction) is the vector cross product of the magnetic field and the electric field.. See
http://en.wikipedia.org/wiki/Poynting_vector
Bob S

 

[astrokreng]

I understand your doubts and it is important to question and seek clarification on scientific concepts. The skin effect is a well-established phenomenon in electromagnetism, where high frequency currents tend to flow on the surface of a conductor rather than through its entire cross-section. This is due to the resistance of the conductor increasing with frequency, causing the current to concentrate on the outer layer where the resistance is lower.

Regarding your first doubt, it is important to note that the voltage alone does not determine the flow of electrons in a conductor. The resistance of the conductor, which is dependent on its material and length, plays a significant role in determining the flow of electrons. In the case of electricity transmission, the conductors used are typically made of materials with low resistance, such as copper or aluminum, and they are designed to minimize losses over long distances.

As for your second doubt, it is true that an alternating magnetic field is created around the conductor during the propagation of electricity. However, this does not necessarily mean that the skin effect would limit the propagation to just a few millimeters or centimeters. The skin depth, which is the depth at which the current is reduced to 1/e (about 37%) of its original value, is dependent on the frequency of the current. At the frequencies used in electricity transmission, the skin depth is typically much larger than the diameter of the conductor, allowing for efficient transmission over long distances.

In conclusion, the skin effect is a well-understood phenomenon in electromagnetism and is taken into consideration in the design and operation of electrical transmission systems. I hope this helps clarify any doubts you may have had. Keep questioning and seeking answers, it is the foundation of scientific progress.