Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Faraday Cage Applied to Power Lines to Negate Field Interference

  1. Jul 17, 2012 #1
    Hello learned Engineers, Physicists, and people more useful than myself:

    Thank you in advance for reading. I would like to submit a more educated proposal to a utility company for a method that would allow it to install 500 kilovolt renewable power transmission lines through many residential neighborhoods that meets the demands of the homeowners, city, and utility company.

    I did some research and what may or may not cause leukemia, harm to pregnant women, and electronic pacemakers but certainly the ire of nearby residents are the magnetic fields resulting from the transmission lines. The noise is also quite unbearable.

    Would a triple layered fine copper mesh absorb sound and block magnetic fields from escaping?

    Are there any specifications to the material that would be required to do such?

    Any ideas at all as to how those transmission lines could be made soft and cuddly?
  2. jcsd
  3. Jul 17, 2012 #2


    User Avatar
    Science Advisor

    A copper shield will not have any effect on magnetic fields unless it is used for the return path of the current.

    Shields will attenuate electric fields, but not magnetic fields.

    I can't suggest any solution though.

    High voltage power lines generally have currents flowing in opposite directions in the wires and the net radiation is close to zero.

    There does seem to be evidence that proximity to power lines will produce health problems, however high voltage power lines generally run along major roads which have high traffic flow. So, there may be an effect due to the pollution from traffic which is getting blamed on the power lines.

    The actual problem with high voltage power lines may be that nobody likes the look of them, but claiming they cause health problems is more likely to get action than objecting to the appearance of the power lines.
  4. Jul 24, 2012 #3
    Thank you vk6kro, I'm finding that transmission lines generate electro-magnetic fields or EMFs. I think that's an electric field, but am not certain if that's just an electric field or if its a magnetic field that is the kind you can not block with copper...

    Guessing this is a no-brainer, but I would appreciate your answer: electro-magnetic fields are electric fields or magnetic fields?

    Do 500 kv power transmission lines create heat? And if the lines do generate their own heat, is it a significant amount?

    I'm guessing it's both, but would housing the transmission line within one of those AC vent/hoses and then applying temperature and humidity control to the air tight hose kill two birds with one stone? The first being the heat problem and the second being the corona noise from high humidity. I know this solution may sound ludicrous due to cost, but from a pure cost standpoint, it is likely much cheaper than the cost of placing them underground and maintaining a 20+ mile long 6 foot wide 30 foot deep trench across a city).

    Any and all educated responses to the positive or negative would be deeply appreciated.

    And if the wire housing were decorated to look like a vine or the sky or a robotic appendage, (but probably something more agreeable to most), it wouldn't look too bad.
  5. Jul 24, 2012 #4


    User Avatar
    Gold Member

    redhand22, Welcome to Physics Forums!

    Will you please explain what are "500 kilovolt renewable power transmission lines"?

    I notice that in every single country on earth electric power is generated, stepped-up to high voltage, sent on transmission lines towards populated areas to sub-stations where it gets stepped down in huge transformers, and then sent around the municipal residential and business areas at a lower voltage, and then distributed locally, where we always see those hanging can-like transformers which step the voltage down to 110 Volts (here in the US), so it can be used by the customer. Now, do you think there must be some good reasons electric power is transmitted and distributed in this manner?

    If your plan to send electric power "through many residential neighborhoods" was implemented, how could the customer interface with the 500,000 Volts passing in front of her home? Have you looked at 500KV transmission equipment? For example, one polymer suspension insulator to withstand 500 KV would weigh about 30 kg and would need a minimum of 3.5 to 4 meters arcing distance clearance. The physical size of the High Voltage equipments is massive, and the cost is very high. Lower voltages need smaller and cheaper insulators, transformers, and becomes simpler to distribute.

    I suggest you read this Wiki page on Electric Power Transmission. It includes some information about human health (non) effects as well:

  6. Jul 24, 2012 #5
    Check it out:


    They are 200 feet tall. Not for the spreading to homes but to transport to substations. The towers are larger than anything I've ever seen or have been able to find.

    I read the wiki on a few related subjects. Its unusual for them to be so close to homes. But something has to be done to mitigate their effects on property values, which happens to cover any harmful effects to people since nearby harmful things generally destroy property values.

    It does seem that having such heavy duty power lines nearby can possibly cause health issues related to EMF, but that's not relevant at this point since the comission has ordered consideration of an option that preliminary studies priced at more than $200 million more expensive than finishing the overhead lines. Anything that's cheaper than $125 million that negates the problems of noise, appearance, and safety should be preferable.

    So those lines need 3.5-4 meters of distance away from anything flammable or anything in general?

    Attached Files:

  7. Jul 24, 2012 #6


    User Avatar

    Staff: Mentor

    Personally, I think we should be burying our power lines. They'd use less land and be more reliable due to lack of issues with trees.
  8. Jul 24, 2012 #7


    User Avatar
    Science Advisor

    Be careful with the abbreviation EMF (Electro Motive Force). This is used for a source of power and is not the same as Electro Magnetic radiation, like light or radio waves.

    Radiation in the form of Electro Magnetic Radiation is extremely small at 50 Hz or 60 Hz because of the very low frequency. Most of the power stays in the wire.

    There is a magnetic field around any wire that carries a current and power lines are no different.

    However, as I mentioned, the magnetic fields tend to cancel each other out at ground level because the currents are flowing in different directions, so the fields have opposite polarities.

    This also applies to the electric voltage gradient due to the voltage from the wires to the ground.

    Yes, the wires of a transmission line do dissipate heat, but they are very well ventillated and are not allowed to get hot enough to damage themselves by melting the conductors.
    Because of the very high voltages used for long distance transmission lines, only a small percentage of the total power is lost due to heat in the wires.
  9. Jul 24, 2012 #8
    When I first saw the towers, I thought monumental instead of eye sore. People keep building enormous towers throughout history, which might be related to some psychological thing to do with phallic symbols according to some experts...haha

    Undergrounding does allay all doubts of appearance, safety, and noise. It is much more expensive to dig a 6 foot wide, 30 feet deep, 20+ mile long tunnel across several cities. The reason these towers are even being built is to incorporate new technology in energy production. Why not involve technologies a little more exciting than trench digging?

    Spend a little to make the towers so well anchored that you could use it as a catapult to launch something very heavy very very far and find that it makes the possibility of the tower falling to any reason unbelievably remote.

    Incorporate some way to shield Electro magnetic fields using advanced materials and now the power lines happen to create no noise or disturbance and look like scintillating beads of a necklace hanging above the horizon.

    If there's a cheaper way to incorporate provable methods that negate all the negative effects and include deals that increase nearby property values, shouldn't it be the solution?
  10. Jul 24, 2012 #9

    jim hardy

    User Avatar
    Science Advisor
    Gold Member


    http://webecoist.com/wp-content/uploads/2011/05/land-of-giants-pylon-competition-1.jpg [Broken]

    the industry has been trying to incorporate aesthetics into their tower and insulator design since 1960's that i know of.

    Observe various high lines for incorporation of divine proportion, cantilevered supports, graceful curves and the like.
    Last edited by a moderator: May 6, 2017
  11. Jul 25, 2012 #10


    User Avatar
    Gold Member

    Excellent HV transmission towers, Old Jim! Reminds me of the Yin-Yang (Female-Male) cooperation in carrying energy!
  12. Jul 25, 2012 #11


    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    I believe that the cost of buried cables is at least ten times the cost of equivalent overhead cables. That's why they only bury them when there's no alternative.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook