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

Power Lines

  1. Jun 30, 2005 #1
    I was out stargazing tonight in the middle of nowhere. Theres plenty of washes out in the skirts of our suburb and I drove out into one of them to avoid city lights. After about ten minutes I started noticing a small clicking sound, kind of like that of static electricity or a small spark, and was curious where it was coming from.
    I looked around and I noticed there were some of those huge power line towers running right behind where I was parked, and the noise started coming from one of those.

    A couple minutes later I started feeling something really intense coming over me and the clicking kept on going, I was laying on top fo my car which was on gravel. Then I started feeling a little tingly and at this point I knew I needed to get the **** out of there so I took a quick dash away from my car. When I realized I wasnt about to get zapped todeath I got back in my car and drove away.

    Anyway, the point of this story is, are those things supposed to be clicking like that? Was I really about to get zapped, or was I just tricking myself into thinking it?

    Appreciate it.
     
  2. jcsd
  3. Jun 30, 2005 #2
    wow, maybe the static was building up around that area of that power line, then maybe it will release a static discharge like a van de graff generator. lol
     
  4. Jun 30, 2005 #3
    Thats what I was fearing but I figured that would be a very very very remote possibility, presuming they take precautions on this sort of thing.
     
  5. Jun 30, 2005 #4

    Gza

    User Avatar

    no, you were probably just high :)
     
  6. Jun 30, 2005 #5
    Sober, this time :wink:

    So its not possible? Was it static discharge that I was hearing? Nothing else really makes sense.
     
  7. Jun 30, 2005 #6

    Danger

    User Avatar
    Gold Member

    It could have been thermal expansion/contraction cycles of the conductors. I don't know where you live, but desert areas get quite cold at night. If the lines and/or towers were hot in daytime and were cooling after the sun went down, all sorts of weird noises could arise. I suppose it's also possible that clouds of insects might bridge between two conductors and create a temporary short, but I've personally never seen a bug cloud dense enough to do that.
     
  8. Jun 30, 2005 #7
    Scottsdale, Arizona

    I think it was about 100 today and probably about 70s-80s that night, so not a big drop. I wasnt near the actual tower, but the wires were just over my head, I'd say about a few dozen feet. There werent any swarms around or any insects that bothered me, and the clickign suond was very familiar, in Sudan there are a few faulty telephone wires that start clicking at the transformer after it rains, it sounded just like it, but there were visible sparks on those, I couldn't see any sparks this time.


    PS, dont forget, tomorrows the grand opening. PM me if you need info.
     
  9. Jun 30, 2005 #8

    Danger

    User Avatar
    Gold Member

    Working on it; thanks for the reminder, though. I'll see what I can dig up amongst my friends around town about the wire thing. I'm assuming that the lines are aluminum, although I don't know if that would make a difference or not. Maybe if there's some sort of irregularity in the resistance at some point, it could cause enough air ionization to form a spark, or maybe the wires just aren't spaced far enough apart.
     
  10. Jun 30, 2005 #9

    Astronuc

    User Avatar

    Staff: Mentor

    High voltage transmission lines have an audible hum (at 60 Hz, which is AC frequency in US) called "corona hum", or "corona noise". Noise levels will vary (30-50 dBA normally) according voltage and cable conditions (which are usually multi-strand aluminum).

    Any clicking sound could be an arc (or short) and may indicate a discontinity in surface of the cable or a dirty or flawed (cracked) insulator. Bird droppings, mold, moss are common contaminants - as are particulates, basically whatever is in the air that might settle from air or condensation.

    Nowadays utilities use microprocessor relay systems to monitor the power lines (and grid) to detect potential faults.

    IIRC - 115 kV, 138 kV, 240 kV, 345kV, 500 kV, 765 kV are common voltages and the sound will increase with voltage (energy).

    Here is a site with some arcing discharges - http://205.243.100.155/frames/longarc.htm

    Download the mpegs and then play them. :biggrin:
     
    Last edited by a moderator: Jun 30, 2005
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Power Lines
  1. Force on 2 power lines (Replies: 13)

Loading...