What causes power lines noise? Especially high voltage power lines?

Shouldn’t they just be silently be transmitting electronic information?

Many people find that noise annoying. And possibly even a sign of danger! Here’s a video for you to hear what it is like:

Of course, this is a bigger issue if you’re living near power lines in the first place versus just chancing by some noisy ones while walking one day.

This gets a bit technical.

This is known as “corona discharge,” where the voltage in the cable is too high for the air around it. This discharge creates the sound as the air actually becomes a partial conductor around 10,000 volts per inch.

This discharge can sometimes be seen as a soft glow of light around the lines. It’s not just power lines noise and light, but means a waste of power as the transmission is “leaky”. Brett Olsen had this picture in his article about this effect.

(This is the same thing as the buzzing that occurs in radio receivers too, but on a lesser level.)

On your average day you’re not likely to find this happening, but it occurs more often in certain environmental situations such as:

• After rain, where the added moisture in the air, added conductivity is added as well.

• Foggy or extra humid days for the same reasons.

It is also more likely to happen on sharp points, corners and cracks in equipment, meaning this will likely happen more if the power lines are not maintained well.

This is more likely with higher voltage power lines and not so likely with low power distribution lines near most homes. Here’s another video:

Those in the industry have learn of this over time and know how to construct power lines to make no noise in normal conditions. But that doesn’t mean that everywhere and all conditions will make this happen.

Note that this is a different reason for the hum or noise you hear from other electric sources. With transformers the cause is magnetostriction.

Is there added danger or risk to power lines making noise as compared to those that don't? Obviously, you want to avoid touching power lines whether they’re quiet or noisy. But overall these shouldn’t be any more dangerous or less dangerous as far as negative EMF’s are concerned.

For the EMF sensitive, you can stand under a noisy power line and notice if you feel any different. And if you do, then be sure to try it while carrying a Blushield Portable with you and notice the difference.