Balls ! - on power lines

loz

Can anyone tell me what the ball thingys are on powerlines - seen when a line crosses over a main road or motorway ?

grimloch

theyre marker balls, designed to stop low flying aircraft/helicopters from flying into the cables

Trojan

Makes them more visible so pilots will see them.

dregin

Why only over roads though?
So there's less chance of ****in up anyone else other than themselves?

grimloch

Helicopters tend to fly over roads if theyre following traffic or chasing a car like or getting news footage

Either way the lines are apparently alot harder to see form the air

DeBeere

Helicopters will follow a road/traintrack/river in low visibility to get their destination.

Powerlines are extremely hard to make out on a clear day so you can imagine how much of a ***** they are when you can barely see where your flying to.

Also if a small fixed wing needs to make an emergency landing it is possible for them to use an empty road without hitting into powerlines

Adam

On the same topic, what is the point of those porcelein (sp?) discs on the lines just next to the poles? I was told they're porcelein but isn't porcelein an insulator, at least when it comes to electricity???

grimloch

The ones that support the electrical wires?, theyre insulators afaik.

Lord Nikon

fade_to_grey wrote:

On the same topic, what is the point of those porcelein (sp?) discs on the lines just next to the poles? I was told they're porcelein but isn't porcelein an insulator, at least when it comes to electricity???

They are actually ceramic, stronger than porcelain. Don't know what they do though.

corkman26

the 'ball thingys' actually serve 3 purposes, they allow for expansion and contraction of the lines, they are indeed markers for aircraft, and they deter birds, allegedly, but they are only found on high voltage lines, (38kv) and over. the ceramic pieces are actually insulators, so that the electricity cannot travel through the metal, and earth through the pole, thus exploding the pole! and everything around it! seen that once actually!

air

The ceramic insulators provide a mechanical connection between the cable and the pylon to support the cable.
The power is looped around the insulator and on to the other side of the pylon thereby allowing the electricity to continue on its way.
I'd be surprised if the "balls" have anything to do with expansion / contraction, the length of the wires is not that critical.

Capt'n Midnight

The balls are red and white because that frightens birds they being simple creatures you don't need hawk shapes. Nearly convinced a bird they were like fishing floats, in case of flooding, but she twigged a little later.

The ceramic insulators do conduct a bit and they heat up because even though it's a tiny current it at very high voltage. They use helicopters with thermal imaging to look for cool insulators, they have been short circuited.

air

Capt'n Midnight wrote:

The ceramic insulators do conduct a bit and they heat up because even though it's a tiny current it at very high voltage. They use helicopters with thermal imaging to look for cool insulators, they have been short circuited.

A bit off the mark here, the insulators do fail but if they shorted you certainly would know about it! 220kv heading to earth through a pylon would be quite spectacular.
The infra red cameras pick up the slight heating that occurs in the early stages of insulator break down and allows the network preselect individual insulators for replacement.
Corona imaging cameras are now superceding thermal imaging cameras as they detect insulation breakdown earlier and more easily.
Electrical corona are caused by ionization of the air around the insulator.

http://www.gisdevelopment.net/aars/acrs/1989/q/ps024.shtml
http://www.corona-technology-course.com/cor-faq.html

fatherdougalmag

There y'go. I always thought that they were weighted somehow so that if they every came down (over a road) they would immediately drag the cable downward toward the pyloon out of harms way.

Now, that fecking ball outside Naas with all the road markings. Is it a time capsule or what? All the years I was on JJ's bus down to Carlow, there were lots of theories but that's the one that I heard from someone living in Naas.

Capt'n Midnight

ye learn something new ever day.. always thought it was the failed insulator that was colder than the others.

There'd be more than one insulator in series so if one failed it would not be catostrophic.

As for new ways of detecting faults, I bet the power station guys prefer the ultrasonic yokes for checking for steam leaks than the old rag on a stick approach.

air

fatherdougalmag wrote:

There y'go. I always thought that they were weighted somehow so that if they every came down (over a road) they would immediately drag the cable downward toward the pyloon out of harms way.

I have to say..... You've lost me! What are you on about??

air

Didnt mean to offend or anything, but I did find that seriously amusing.
As for a weight pulling the cable "clear of harms way", those cables weight a serious amount (try holding up even 20ft of it while changing a pantograph in the compound).
I dont think a plastic ball would do much of a job recoiling 100m of it

fatherdougalmag

Yes, pyloons as opposed to pylons.

Here on Planet Dougal things aren't as they are on your so called 'earth'.

It was somebody from Laois who had actually suggested it and, at 9.44 in Tullys of a Thursday night in old Carlow town, it was the best theory on offer so it stuck. Maybe the plastic balls are filled with something other than air down there but I don't know.

As for helicopters following roads in poor visbility conditions and expecting to catch sight of a red and white ball before they got tangled up, I don't know. Maybe the balls have a mechanism built inside that'll do the trick.

Tell you what. There's one down the road from me. I'll go down and see what happens when I hack through it with a pair of Balamory scissors. If you don't hear from me in the next few days then watch the news. And if you don't see anything there, well, death by very-mis-adventure.

fatherdougalmag

while changing a pantograph in the compound

.

I lost you, you lost me. Let's call it quits. Sounds like a Pink Floyd song if you ask me.

Victor

Capt'n Midnight wrote:

The balls are red and white because that frightens birds they being simple creatures you don't need hawk shapes.

So why are they only at specific points like roads and railways?

Some / all also illuminate at night.

Blisterman

fatherdougalmag wrote:

Now, that fecking ball outside Naas with all the road markings. Is it a time capsule or what? All the years I was on JJ's bus down to Carlow, there were lots of theories but that's the one that I heard from someone living in Naas.

Good question. What is that? Does anyone know?

air

fatherdougalmag wrote:

.

I lost you, you lost me. Let's call it quits. Sounds like a Pink Floyd song if you ask me.

Its a piece of equipment in a substation that needs to be serviced occasionally.
Its looks like a breaker but it doesnt actually perform the breaking, it just serves as a mechanical (visible) indicator that the lines have been disconnected to allow servicing.

As for the birds / roads issue, I'm not too sure, maybe they dont want dead birds falling onto the roads?

qwertz

Afaik, the balls are only there for the helicopters and planes (wee ones). They don't have a mechanical mechanism inside them. The power lines extend and contract quite a bit anyway, depending on the temperature.

SparrowHawk

I remember being told many years ago that they were to allow for expansion & contraction.

SH

joejoem

Capt'n Midnight wrote:

The balls are red and white because that frightens birds they being simple creatures you don't need hawk shapes. Nearly convinced a bird they were like fishing floats, in case of flooding, but she twigged a little later.

The ceramic insulators do conduct a bit and they heat up because even though it's a tiny current it at very high voltage. They use helicopters with thermal imaging to look for cool insulators, they have been short circuited.

Ha ha I convinced my cousin that Tu Pac had made a comeback and he was alive but fat and old looking but that he had released a new song all about how he had to go into hiding.

Victor

Blisterman wrote:

Good question. What is that? Does anyone know?

It's a piece of art.