What frequency(s) is the electromagnetic radiation from high voltage power lines?

What frequency(s) is the electromagnetic radiation
from high voltage power lines?

Is there an instrument that can detect underground
high voltage lines ?

 

Depends on what country you're in. Here in the US, it *SHOULD* be 60Hz,
although it may "sag" a little from time to time, and there may be
harmonics. In the UK and most (all?) of Europe, they run 50Hz AC. Those
are your "base" points to start looking for emissions - nothing says
there can't be other schemes used in other places.

Yes, "line hunters" are available that will spot underground lines. Like
everythign, I'm sure there are the ones that are lousy, and the ones tat
are superb at it, but don't ask me to distinguish between the two
without a WHOLE LOT more info and some "hands-on" playing with them.

 

You probably don't want to detect "electromagnetic radiation" at 60hz, since you
need a really long antenna to recieve 60hz electromagnetic radiation...the
wavelength at that frequency is around 5000km. Most anything you detect in the
60hz realm is near field (inductive).

 

The safest way to find underground high voltage lines is to call the power
company.

 

In the USA, the power grid is divided into several regions.
Within each the frequency is 60 Hz. But there are also
interties between regions, and since it would be too
difficult to keep all the regions in perfect sync, the interties
are DC. When I first found out about this I couldn't
believe it, but they actually have to go through conversion
processes at both ends. Have to wonder how they do
this at a gazillion amps and keep the losses from
melting the equipment!


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

 

If you want to find overhead powerlines use a kite.

 

Assuming that BT really is your ISP, I suspect you are here in the UK... The
mains supply is 50Hz.

 

This does not make any sense at all. Everyone here
says that the the requency is 50 Hz. I know the
electricity works at 50 Hz, this does not mean that
the electromagnetic waves of high power cable lines
are 50 Hz. For example, whenever I drive near high
voltage lines my am radio goes all haywire. This means
that at least some of the radiation is at 100 - 1600
KILO Hertz. I can't believe someone suggested to build
a 5000 km antenna to test these waves, I assume he was
making some sort of joke of my question. Obviously, any
detector should be smart enough to use a detection
method which doesn't involve builing a 5000 km antenna.

 

If you are getting noise on your broadcast radio why not use a small
portable receiver and find the place where the noise is strongest -
should put you in the general area.

Dave

 

He's talking about the frequency of the radiation itself, guys. If you turn
a red light on and off at 60 Hz, that doesn't mean the light is radiating at
50 Hz.

Don

 

Not at all - all that means is that sufficiently strong 50 Hz
fields are capable of inducing noise in your radio. Surely
you don't believe that ONLY "100-1600 kHz" fields are
capable of affecting your radio, do you?

The frequency of the AC power is 50 Hz (in the UK), and
therefore the fields around the lines are also 50 Hz, and
essentially ONLY 50 Hz.

Bob M.

 

If the radio's any good, they are.

This is not accurate, if there's a fault in the line of
some kind, like a corona. Even dirty insulators can do it.
There's a nonlinear conductor of some kind in the circuit,
and it makes harmonics every 50 (or 60) Hz up to as high
as you can detect.

If your AM radio gets interfered with, tell the power company.
They'll want to know, because there's a loss in their line
somewhere.

And if you don't believe me, ask _them!_

Cheers!
Rich

 

Think about it- what your radio is picking up is not the 50 hz
electrical field. It can't. What you are in fact detecting is noise from
arcing losses, or from non-linear elements in a transformer, or any number
of other things.
Any time you rapidly switch something, from tiny arcing losses or from
corrosion on a contact, or even from a simple square wave, you generate RF
harmonics. That is what you are picking up. You would need an antenna that
was about 6000 km in length (or some nice handy multiple or fraction of
that) to effectively pick up 50 hz electromagnetic waves.

Cheers!

Sir Charles W. Shults III, K. B. B.
Xenotech Research
321-206-1840

 

-----------
A major couse of RF interference from power lines is due to corona
discharges due to high fields near the conductors. Broad frequency noise
from audio to TV frequencies can occur. Sometimes it is due to corona
discharges at points such as the ends of tie wires on insulators, sometimes
loose connections on hardware in regions of high field intensity, sometimes
due to contamination on insulator surfaces. Often low voltage (33KV or so)
lines are worse than EHV (330KV or more) are worse culprits (sharp points).
On High voltage lines, contamination of insulators, nicks or crap on the
conductors, etc are more prevalent.
In areas where this is a problem, the utility is (or should be) responsible
for reduction/mitigation of the problem.
Normal 50/60 Hz will not be a problem. Harmonics of 50/60 Hz that may exist
will also not be a problem. (25th harmonic of 60 Hz is at 1500Hz and will be
extremely small as well as not being in the "RF" range).

 

And if you did pick up 50Hz (which is easy to do accidentally in the
near field) it's AF and you'd hear it as a low hum.

Chris

 

Ah, right you are. Thanks.

Don

 

But his question comes from noise heard on an AM
radio when in the presence of power lines. Since
those AREN'T switched (at least, not often! ), the
noise in question is almost certainly from induced noise
currents at the power-line frequency.

Bob M.

 

Very, very few radios (or any other consumer electronics)
are completely immune to frequencies outside of the band
of intended reception. Wanna compare EMI susceptibility
horror stories?

And hence the word "essentially." But if you're talking
about the fields you will most commonly encounter, and
the relative power level of these fields, the top of the lists
will always be a big fat magnetic field at the power
frequency.

Agreed, IF the circumstances are such that would suggest
corona discharge as the culprit. That did not seem to be
the case here.

Bob M.

 

It's easy. Just use a lot of insulation. It's only a half a megavolt
DC at 2000 amps. :-O

http://205.243.100.155/frames/longarc.htm#500_kV_Switch

Check this out. This is 1.5MB, so it may take awhile. If the above
doesn't work, then go to www.teslamania.com and use the menues Big Arcs
'N' Sparks.

 

Those aluminaized mylar birthday balloons work much better. One landed
across the 12KV line where I live, took out the whole neighborhood for
over 8 hours. Just that silly little balloon burned out the transformer
and melted the 10 gage aluminum wire.

[snip]