sound in high tension electrical lines

This is called corona effect, happened due to the flow of ionized air between wires,

Or... it is sound caused by the wind generating a vibration in the wires. Quite common. These lines can "sing" by times.

Hello "Guest"

You do not explain what the sound is like.

Perhaps it is

But most probably, as earlier stated, it is corona from ionized air, this is more common on a foggy day - hissing noise.

There could be leaky insulators, or insulators which are dusty, and these give a low crackling sound.

If you are able to describe the sound, it would be helpful.

Likewise a photo of an insulator or insulator string, or advise the line Voltage would assist.

Whatever you do, do not get too close to the wire, as High Voltage (HV) or Extra High Voltage (EHV) is able to easily leap a gap to an earthed or grounded object.

Kind Regards....

Hello gsuhas

Many long years ago, I worked from a live-line "travelling-along-the-conductor" mobile cart.

A modern version is shown at left.

A very interesting effect, particularly if you leaned out too much.

The hair on one's head and arms would stand up. - a constant reminder to remain inside the cart until the power was turned off and the line earthed at a tower on each side of the tower at which we climbed out of the travelling cart.

Our two-man carts were somewhat more elaborate, having handles which the two workers could wind, to travel along the conductor, even up quite steep slopes, brakes, and had extra wheels as well, which enabled the cart to pass insulator strings easily, without disengaging the other wheels from the conductor for the insulator passing operation.

Sometimes the cart yawned over 400-500 foot drops into the river far below, so nerves of steel were needed, particularly if a high wind was blowing at the time.

For those interested, here is a good Weblink: http://www.youtube.com/watch?v=4qoymGCDYzU Enjoy

Kind Regards....

Sparks,

Did you ever ride a helicopter up to the high tension wire, reach out with a wired clamp to make the helo and HT wire the same potential, then climb on the skid and over to the HT wire from which you would then hang and perform your inspection as the helo flew off? Me neither, but there's good video of the fools that do that on the web.

www.alexisparkinn.com/helicopter_videos.htm

Scroll down to "High-Powered Job"

(It is an 8Mb download) Cool video, and sound track.

Hello 1Degreeabove0

Thanks for that excellent Weblink Video.

Mind you, after looking at some of the helicopter crash videos on that site, it makes me think carefully before I ever ride in a chopper again.

I note those workers wear a metallised suit, which minimises electrostatic shock. (The Faraday Cage effect)

Kind Regards....

Hello Kyoto

When I was working on EHV lines, I had never seen a helicopter at close range, juast a few, far away in the sky, and these were far too few and expensive to be used on power-lines work.

It was the early 1960's before I saw near enough to touch it, my first helicopter, which was based on a NZ Navy Frigate, that frigate was sunk on 18 December 2000 as an artificial reef

Heights never worried me, but there were some who had to be "carefully assisted" down from a transmission tower, sometimes strapped to a wide plank, after they thought about where they were.

Those folks either climbed back up at once, or else they never climbed again.

Principle is that fear must be dealt with as soon as possible, or you don't get over it.

Kind Regards....

It is corona.Its breakdown of air around the conductor due to the voltage..Mostly it is prevalent on voltages of 132 KV and above.

if you had that much voltage run thru you, you would be screamin too.

If it is anywhere near a transformer, the sound may be caused by magnetostriction in the transformer, but given your description, this seems unlikely.

Sunspots cause this and all other strange and un-explained electrical phenominal.

this hissing sound is coming due to corona effect or corona discharge.this happens generally on 132kv or above voltage transmission lines.due to this much high voltage strong electric field is developed in between the transmission line (like elec. field developed within the parallel plate capacitor)which accelerates free electrons and ions present in the atmosphere and starts colliding with conductor and gets generating more and more free electrons and ions with each collision .due to these collisions a vilote glow comes into picture which can be seen in dark night through out the line .this glow will be spoty or uniform through out the conductor depending upon the atmosphere,conductor size and conductor surface .

Yes .I have seen that on really dark nights.Also in places where saline atmosphere and high humidity exist even at lower voltage the break down of air occurs.