The best way to think of it is that a load with a low power factor
will move a lot of electricity back-and-forth in the power lines
without actually consuming the energy. You get billed for the amount
of power the load uses, but a higher amount if moving back-and-forth,
and being disipated as heat in the power lines, transformers and so
on. So, there's a real cost to the electricity company, but it doens't
show on the meter. That's why larger industrial users with poor power
factors will be charged for it, and why some install local capacitors
to act as reservoirs to restrict the back-and-forth to their own
premises, thereby avoiding all the waste in the power transmission
Umm, haven't you ever noticed the large banks of capacitors housed outside
many industrial buildings? THOSE are the ones that are correcting for the PF
in that building. The power company does not correct for unknown power
factors and couldn't if it wanted to. I think you're misunderstanding the
purpose of whatever it is you're seeing that you think are cap banks.
Don't know about where you live, but around here I often see racks of PF
correction caps on utility poles - 3 phase distribution voltage.
Utilities certainly DO install them. Utilities may also switch PF
correction caps [which can cause bad surges].
Another good post by George.
Another bad one by Twayne.
Utilities -sometimes- may install them in certain areas, I don't know. I've
never seen it in Coronado, San Diego, Chicago, Aspen, Fort Worth, St. Louis,
Boca Raton, or upsate NY and NYC. Anymore it's all underground anyway except
for smaller cities and rural areas. I've seen a lot of things on power
poles but never a capacitor bank.
Once the plans are approved for their installation by the powerco, a
contractor installs them any where I've ever been. Then they're inspected by
the powerco if it's a big system and they go into use. One of the things
you do often see on a power pole is a repeater for sending the RF received
electrical usage down down the hi-voltage wires for charging for power
I'd appreciate it if you could find a URL or similar source to verify that
they'll put capacitor banks on a power pole. You do realize how much even
small ones weigh, don't you? And what the value of "small" would be? I'm
guessing you don't, but it's easy to calculate. Actually I'm wondering now
if you would even recognize a capacitor bank as capacitors anyway.
But, if I'm wrong, I'd certainly like to see some evidence of it.
Often you'll find excellent advice on a newsgroup.
Before you use that advice though, consider the
Out of some 16,000 hits on "capacitor+bank+power+poles" here's the first -
complete with pictures:
Here's a brochure (PDF) with really colorful pictures (suitable for framing)
OUTstanding, heybub! Thanks for the education, really. I have never seen
them and if I had I'd be sure to have remembered them! At first I thought
they might be all Pac Rim and EU located, but no, there are a few for N.A.
too, so obviously they are used here, IMO.
I sincerely apologize to you; hope you'll accept it. I was wrong and made
suppositions I shouldn't have. I was surprised to see polyprop as the
material, too. Guess I shoulda known better; next time I'll be a lot more
I first saw a rack of PF correction caps about 5th grade. The utility
was installing one on a utility pole next to my school. I asked a
lineman what it was and he told me. Even explained what it did, but in
5th grade it didn't entirely make sense - current when there is no
That rack, and the racks I see about every day, look a lot like the .htm
from HeyBub. The racks may have 3, 6 or 9 caps.
Gotta be way lighter than 3 pole pigs for 3 phase.
ooh - nobody is as smart as Twayne. I have know what PF correction caps
look like since I was about 10. Maybe you don't know what they look like.
HeyBub to the rescue after a difficult google search.
But the power company commonly corrects for PF and does install
capacitors to do it. They know practically none of their customers have
a unity PF and are usually lagging. Their base charges already include
an allowance for that. Not sure why they couldn't correct PF if they
wanted to since all they need to do to correct the typical lagging load
connected to them is install capacitors just like a large industrial
facility might if they want to avoid a PF penalty.
It isn't complicated. Like I said, certain loads put a strain on the
trasnmission system without actually using power. That's all that has
to be said. All this show-boating about phase angles, reactance and
moving the PF back to unity is what is getting in the way.
Power Factor is related to inductive or capacitive loads. It is best
seen if you take it to an extreme with a load that is 100 capacitive.
Lets say you put a capacitor across the line and measure the current
at 10 amps. This current is not doing any work and is returned to the
circuit. It doesnt show up on your electric bill and is not read by
your power meter. This is only more or less true. The more or less
part come in because the cables that carry the current to and from
this capacior are not perfect conductors, they are resistive. The
increased current caused by the capacitor increases loss on the lines.
These losses turn into heat which you will have to pay for. For
resisdential use it wont be very much for industrial use it could be
quite a bit. PoCos also have extra charges for places who have a
highly reactive load because it causes greater losses on the PoCo's
power lines. Their are lots of myths that you can add capacitors or
inductors to reduce your eelctric bill and even get free electricity.
Neither are practical for residetial users. The free electricity myth
isnt true for any type of user.
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