If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.
How would they stay apart during high winds, which
are expected in that part of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

"Andrew" wrote in message
...
If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.
How would they stay apart during high winds, which
are expected in that part of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

That was my thought: if the starlings landing and taking off stretch and
swing the wires so much that they touch, even in cold weather when the heat
hasn't made them expand, then a gale could do the same. The wires need to be
tightened.

On 18/12/2020 13:15, NY wrote:
"Andrew" wrote in message
...
If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.
How would they stay apart during high winds, which
are expected in that part of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

That was my thought: if the starlings landing and taking off stretch and
swing the wires so much that they touch, even in cold weather when the
heat hasn't made them expand, then a gale could do the same. The wires
need to be tightened.

It was a hell of a lot of starlings on each wire. Individually they may
not weigh much but on those numbers and all acting in synchrony they
must be well beyond normal design tolerances.

Our local mains in the village is three phase aluminium core wrapped
around a steel hawser. It proved strong enough to support most of the
weight of a tree. The recoil when the tree was cut free was spectacular!

All the poles in the village are now banana shaped with "do not climb"
warning stickers on them.

--
Regards,
Martin Brown

On 18/12/2020 12:57, Andrew wrote:
If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.
How would they stay apart during high winds, which
are expected in that part of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

I don't think winds normally cause too much problem on 11kV. Trouble is,
they don't produce enough corona discharge to keep birds clear.

On national transmission lines the current they can carry is limited by
sag caused by thermal expansion, so they can carry more power at low
temperatures. A rare example of Sod getting it wrong.

"Martin Brown" wrote in message
...
On 18/12/2020 13:15, NY wrote:
"Andrew" wrote in message
...
If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.
How would they stay apart during high winds, which
are expected in that part of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

That was my thought: if the starlings landing and taking off stretch and
swing the wires so much that they touch, even in cold weather when the
heat hasn't made them expand, then a gale could do the same. The wires
need to be tightened.

It was a hell of a lot of starlings on each wire. Individually they may
not weigh much but on those numbers and all acting in synchrony they must
be well beyond normal design tolerances.

If "synchronous swallows" (!) are more than a once-in-a-lifetime event, then
the design tolerance of the wire tautness and/or wire spacing must be set so
doesn't cause a problem.

Our local mains in the village is three phase aluminium core wrapped
around a steel hawser. It proved strong enough to support most of the
weight of a tree. The recoil when the tree was cut free was spectacular!

All the poles in the village are now banana shaped with "do not climb"
warning stickers on them.

What are the poles made of? For them to be "banana shaped", they must have
bent without breaking, which suggests metal rather than the wooden poles
that are normal for HV and 240 V overhead wires.

On 18/12/2020 13:22, Martin Brown wrote:
That was my thought: if the starlings landing and taking off stretch
and swing the wires so much that they touch, even in cold weather when
the heat hasn't made them expand, then a gale could do the same. The
wires need to be tightened.

It was a hell of a lot of starlings on each wire. Individually they may
not weigh much but on those numbers and all acting in synchrony they
must be well beyond normal design tolerances.


https://www.youtube.com/watch?v=pWIVoW9jAOs


--
Adrian C

In article ,
Martin Brown wrote:
On 18/12/2020 13:15, NY wrote:
"Andrew" wrote in message
...
If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.
How would they stay apart during high winds, which
are expected in that part of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

That was my thought: if the starlings landing and taking off stretch and
swing the wires so much that they touch, even in cold weather when the
heat hasn't made them expand, then a gale could do the same. The wires
need to be tightened.

It was a hell of a lot of starlings on each wire. Individually they may
not weigh much but on those numbers and all acting in synchrony they
must be well beyond normal design tolerances.

Our local mains in the village is three phase aluminium core wrapped
around a steel hawser. It proved strong enough to support most of the
weight of a tree. The recoil when the tree was cut free was spectacular!

All the poles in the village are now banana shaped with "do not climb"
warning stickers on them.

Would insulating them to prevent this actually cost a lot?

--
*Bigamy is having one wife too many - monogamy is the same

Dave Plowman London SW
To e-mail, change noise into sound.

On 18/12/2020 13:34, Dave Plowman (News) wrote:
In article ,
Martin Brown wrote:
On 18/12/2020 13:15, NY wrote:
"Andrew" wrote in message
...
If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.
How would they stay apart during high winds, which
are expected in that part of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

That was my thought: if the starlings landing and taking off stretch and
swing the wires so much that they touch, even in cold weather when the
heat hasn't made them expand, then a gale could do the same. The wires
need to be tightened.

It was a hell of a lot of starlings on each wire. Individually they may
not weigh much but on those numbers and all acting in synchrony they
must be well beyond normal design tolerances.

Our local mains in the village is three phase aluminium core wrapped
around a steel hawser. It proved strong enough to support most of the
weight of a tree. The recoil when the tree was cut free was spectacular!

All the poles in the village are now banana shaped with "do not climb"
warning stickers on them.

Would insulating them to prevent this actually cost a lot?


Yes. Only an idiot or a socialist would even consider it.

The air gap *is* the insulation. The wires look too saggy.

In article ,
Chris Hogg wrote:
On Fri, 18 Dec 2020 12:57:13 +0000, Andrew
wrote:

If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.
How would they stay apart during high winds, which
are expected in that part of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

Is it only starlings that murmurate, or do other birds do it, does
anyone know?

Isn't it a made up word, based on a murmur of starlings?

--
*We have enough youth, how about a fountain of Smart?

Dave Plowman London SW
To e-mail, change noise into sound.

On Fri, 18 Dec 2020 13:31:06 +0000, Adrian Caspersz
wrote:

On 18/12/2020 13:22, Martin Brown wrote:
That was my thought: if the starlings landing and taking off stretch
and swing the wires so much that they touch, even in cold weather when
the heat hasn't made them expand, then a gale could do the same. The
wires need to be tightened.

It was a hell of a lot of starlings on each wire. Individually they may
not weigh much but on those numbers and all acting in synchrony they
must be well beyond normal design tolerances.


https://www.youtube.com/watch?v=pWIVoW9jAOs

Magic, absolute magic!!!

Avpx


--
The truth may be out there, but lies are inside your head.
(Hogfather)
14:50:01 up 12 days, 18:13, 10 users, load average: 11.28, 11.84, 12.04

In article ,
Chris Hogg wrote:
On Fri, 18 Dec 2020 14:23:37 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
Chris Hogg wrote:
On Fri, 18 Dec 2020 12:57:13 +0000, Andrew
wrote:

If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.
How would they stay apart during high winds, which
are expected in that part of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

Is it only starlings that murmurate, or do other birds do it, does
anyone know?

Isn't it a made up word, based on a murmur of starlings?

Oh very likely, but I was meaning that spectacular swirling about in a
flock that starlings do. Other birds fly in flocks, but do any of them
murmurate like that?

It's amazing to watch. If only 'strictly' had that degree of control.

--
*Be more or less specific *

Dave Plowman London SW
To e-mail, change noise into sound.

On 18/12/2020 12:57, Andrew wrote:
If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.

It is difficult to see, but they don't look particularly saggy to me
once they settle after the birds have taken off.

How would they stay apart during high winds, which
are expected in that part of the country ?..

In high winds, they ought to all blow in the same direction, rather than
bounce about randomly.

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891


--
Colin Bignell

On Fri, 18 Dec 2020 16:11:44 +0000 (GMT), "Dave Plowman (News)"
wrote:

snip


It's amazing to watch.

Animals are amazing and most show us to be the pathetic creatures we
really are.

With great (albeit artificial) power comes great responsibility and
that includes protecting not exploiting and killing those around us,
*especially* for no real reason.

Millions of years after birds could fly together in vast numbers, man
has just managed to get some drones doing a fraction of what even a
starling can do (but not the flying nearly 1000 miles in one go). ;-)

Cheers, T i m

On 18/12/2020 13:34, Dave Plowman (News) wrote:
In article ,
Martin Brown wrote:
On 18/12/2020 13:15, NY wrote:
"Andrew" wrote in message
...
If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.
How would they stay apart during high winds, which
are expected in that part of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

That was my thought: if the starlings landing and taking off stretch and
swing the wires so much that they touch, even in cold weather when the
heat hasn't made them expand, then a gale could do the same. The wires
need to be tightened.

It was a hell of a lot of starlings on each wire. Individually they may
not weigh much but on those numbers and all acting in synchrony they
must be well beyond normal design tolerances.

Our local mains in the village is three phase aluminium core wrapped
around a steel hawser. It proved strong enough to support most of the
weight of a tree. The recoil when the tree was cut free was spectacular!

All the poles in the village are now banana shaped with "do not climb"
warning stickers on them.

Would insulating them to prevent this actually cost a lot?


A Buzzard shaped kite would be cheaper.

--
Colin Bignell

Andrew wrote:
On 18/12/2020 13:34, Dave Plowman (News) wrote:
In article ,
Martin Brown wrote:
On 18/12/2020 13:15, NY wrote:
"Andrew" wrote in message
...
If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.
How would they stay apart during high winds, which
are expected in that part of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

That was my thought: if the starlings landing and taking off stretch
and
swing the wires so much that they touch, even in cold weather when the
heat hasn't made them expand, then a gale could do the same. The wires
need to be tightened.

It was a hell of a lot of starlings on each wire. Individually they may
not weigh much but on those numbers and all acting in synchrony they
must be well beyond normal design tolerances.

Our local mains in the village is three phase aluminium core wrapped
around a steel hawser. It proved strong enough to support most of the
weight of a tree. The recoil when the tree was cut free was spectacular!

All the poles in the village are now banana shaped with "do not climb"
warning stickers on them.

Would insulating them to prevent this actually cost a lot?


Yes. Only an idiot or a socialist would even consider it.

The air gap *is* the insulation. The wires look too saggy.

There's only so much tension you can apply to lines,
without the lines failing. They're not intended to be
strung like guitar strings. The tension is somewhat
irrelevant if the stretch was in a straight line,
but when the transmission curves gently across terrain,
there need to be guy wires to counteract the forces
involved.

When a line touches the ground, now it's too loose :-)

"Suggested Practices for Avian Protection On Power Lines"

https://www.nrc.gov/docs/ML1224/ML12243A391.pdf

Making the crossarms a bit wider might help.
Maybe the next time they replace all the poles, they
could change the crossarm design.

Paul

On 18/12/2020 16:38:36, T i m wrote:
On Fri, 18 Dec 2020 16:11:44 +0000 (GMT), "Dave Plowman (News)"
wrote:

snip


It's amazing to watch.

Animals are amazing and most show us to be the pathetic creatures we
really are.

With great (albeit artificial) power comes great responsibility and
that includes protecting not exploiting and killing those around us,
*especially* for no real reason.

Millions of years after birds could fly together in vast numbers, man
has just managed to get some drones doing a fraction of what even a
starling can do (but not the flying nearly 1000 miles in one go). ;-)

This is pretty impressive:
https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird

Maximum speed: 1,910 kn (2,200 mph, 3,540 km/h) at 80,000 ft (24,000 m)
Maximum speed: Mach 3.32[N 5]
Ferry range: 2,824 nmi (3,250 mi, 5,230 km)
Service ceiling: 85,000 ft (26,000 m)
Rate of climb: 11,820 ft/min (60.0 m/s)

I'm not sure how many starlings can beat that?

On Fri, 18 Dec 2020 18:08:44 +0000, Fredxx wrote:
This is pretty impressive:
https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird

Maximum speed: 1,910 kn (2,200 mph, 3,540 km/h) at 80,000 ft (24,000 m)
Maximum speed: Mach 3.32[N 5]
Ferry range: 2,824 nmi (3,250 mi, 5,230 km)
Service ceiling: 85,000 ft (26,000 m)
Rate of climb: 11,820 ft/min (60.0 m/s)

I'm not sure how many starlings can beat that?

OK, a clear win on speed - no bird can exceed the speed of sound, and
given how energy inefficient supersonic flight is it's hardly surprising.
Birds have made it to 37,000 ft which is the same height as commercial
airliners but doesn't come near the Blackbird.

But birds have been tracked flying non-stop for 7,500 miles, and the
swift can stay airborne for 10 months (and probably longer if they didn't
have to land to raise chicks). The largest ever formation of aircraft
(drones) seems to be just over 3000, while the largest recorded starling
murmuration is about 6 million.

It's the same as in many fields - human technology wins easily on raw
power, but struggles to match nature in efficiency and control.

Mike

On 18/12/2020 13:25, newshound wrote:
I don't think winds normally cause too much problem on 11kV.

Then you are wrong. Especially near trees. Mind you in the last 20 years
they have cut nearly all the trees back near thenm round here, which has
helped, but gales still cause brownouts


Trouble is,
they don't produce enough corona discharge to keep birds clear.

Neither do teh 275Kv ones, Ive seen birds on those.

On national transmission lines the current they can carry is limited by
sag caused by thermal expansion, so they can carry more power at low
temperatures. A rare example of Sod getting it wrong.

I don't think that is correct either. There isn't much sag before
melting on a hot wire.

In reality losses get too great at high currents - I²R etc etc.




--
A lie can travel halfway around the world while the truth is putting on
its shoes.

On Fri, 18 Dec 2020 21:44:01 -0000 (UTC), Mike Humphrey
wrote:

snip

OK, a clear win on speed - no bird can exceed the speed of sound, and
given how energy inefficient supersonic flight is it's hardly surprising.

Quite, and all the resources doing so would use and the pollution it
would create.

Birds have made it to 37,000 ft which is the same height as commercial
airliners but doesn't come near the Blackbird.

Because there is no need to. ;-)

But birds have been tracked flying non-stop for 7,500 miles, and the
swift can stay airborne for 10 months (and probably longer if they didn't
have to land to raise chicks).

Yup, amazing (to us). 'Perfectly natural' to them, with what they were
born with.

The largest ever formation of aircraft
(drones) seems to be just over 3000, while the largest recorded starling
murmuration is about 6 million.

Boom! ;-)

It's the same as in many fields - human technology wins easily on raw
power,

Yup, 'human technology', not 'humans'. A human wouldn't even win on
raw strength against a chimp.

Nor would we with on speed or memory:

https://www.youtube.com/watch?v=ravykEih1rE

but struggles to match nature in efficiency and control.

The reason some seem to miss just how pathetic we are (in a 'nature /
survival POV') also think we are at the top of the tree and so
therefore can do what we like with anything else (except as we evolve
ourselves and realise we also rely on these creatures for our own
survival (and not food) that's slowly that's changing of course).

e.g. https://ibb.co/RHWFbVN

To see just how well we will all cope in nature we just need a
worldwide EMP. ;-)

Cheers, T i m

On 19/12/2020 04:35, The Natural Philosopher wrote:
On 18/12/2020 13:25, newshound wrote:
I don't think winds normally cause too much problem on 11kV.

Then you are wrong. Especially near trees. Mind you in the last 20 years
they have cut nearly all the trees back near thenm round here, which has
helped, but gales still cause brownouts


Trouble is, they don't produce enough corona discharge to keep birds
clear.

Neither do teh 275Kv ones, Ive seen birds on those.

On national transmission lines the current they can carry is limited
by sag caused by thermal expansion, so they can carry more power at
low temperatures. A rare example of Sod getting it wrong.

I don't think that is correct either. There isn't much sag before
melting on a hot wire.

Yes there is. I spent most of my childhood on the farm behind where
I lived and there were a number of ?132Kv pylon routes passing through
their fields and on a hot August day it was very noticible that the
wires were closer the ground than in winter.


In reality losses get too great at high currents - I²R etc etc.

On 18/12/2020 16:11, Dave Plowman (News) wrote:
In article ,
Chris Hogg wrote:
On Fri, 18 Dec 2020 14:23:37 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
Chris Hogg wrote:
On Fri, 18 Dec 2020 12:57:13 +0000, Andrew
wrote:

If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.
How would they stay apart during high winds, which
are expected in that part of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

Is it only starlings that murmurate, or do other birds do it, does
anyone know?

Isn't it a made up word, based on a murmur of starlings?

Oh very likely, but I was meaning that spectacular swirling about in a
flock that starlings do. Other birds fly in flocks, but do any of them
murmurate like that?

It's amazing to watch. If only 'strictly' had that degree of control.

It isn't really "control", though. Like swarms of fish they are just
following a simple algorithm that says keep close to the next bird(s),
but far enough away to take avoiding action if they get too close. They
end up in a very ordered array with almost crystalline spacing, which is
why you see the sudden dark bands depending on your alignment.

It's only the perturbations when the edge gets close to an obstacle like
a tree or the ground that generate the illusion of overall control. You
see the same thing in 2d on skating rinks, just not with the same
numbers. You might have substantial numbers of vehicles on a busy
multi-lane motorway, but then that's (almost) 1d.

On 18/12/2020 13:34, Dave Plowman (News) wrote:
In article ,
Martin Brown wrote:
On 18/12/2020 13:15, NY wrote:
"Andrew" wrote in message
...
If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.
How would they stay apart during high winds, which
are expected in that part of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

That was my thought: if the starlings landing and taking off stretch and
swing the wires so much that they touch, even in cold weather when the
heat hasn't made them expand, then a gale could do the same. The wires
need to be tightened.

It was a hell of a lot of starlings on each wire. Individually they may
not weigh much but on those numbers and all acting in synchrony they
must be well beyond normal design tolerances.

Our local mains in the village is three phase aluminium core wrapped
around a steel hawser. It proved strong enough to support most of the
weight of a tree. The recoil when the tree was cut free was spectacular!

All the poles in the village are now banana shaped with "do not climb"
warning stickers on them.

Would insulating them to prevent this actually cost a lot?

Not really.

Many of the distribution single phase wires in villages start out with
insulation on them but after a few decades it perishes and hangs down in
strips arcing and sparking in the rain when it touches another phase.
Sometimes it was bad enough to trip out the circuit breaker.

Ours used to be like that before they replaced it with the modern
composite aluminium cable with the internal steel hawser.

--
Regards,
Martin Brown

On 20/12/2020 13:26, Martin Brown wrote:
On 18/12/2020 13:34, Dave Plowman (News) wrote:
In article ,
Â*Â*Â* Martin Brown wrote:
On 18/12/2020 13:15, NY wrote:
"Andrew" wrote in message
...
If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.
How would they stay apart during high winds, which
are expected in that part of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

That was my thought: if the starlings landing and taking off stretch
and
swing the wires so much that they touch, even in cold weather when the
heat hasn't made them expand, then a gale could do the same. The wires
need to be tightened.

It was a hell of a lot of starlings on each wire. Individually they may
not weigh much but on those numbers and all acting in synchrony they
must be well beyond normal design tolerances.

Our local mains in the village is three phase aluminium core wrapped
around a steel hawser. It proved strong enough to support most of the
weight of a tree. The recoil when the tree was cut free was spectacular!

All the poles in the village are now banana shaped with "do not climb"
warning stickers on them.

Would insulating them to prevent this actually cost a lot?

Not really.

Many of the distribution single phase wires in villages start out with
insulation on them but after a few decades it perishes and hangs down in
strips arcing and sparking in the rain when it touches another phase.
Sometimes it was bad enough to trip out the circuit breaker.

Ours used to be like that before they replaced it with the modern
composite aluminium cable with the internal steel hawser.


The cables in question are carrying 11Kv, not 230V and have been
there for decades. Insulated wires would be too heavy for the
existing poles and supports. Why would they bother, especuially
when only 50 houses are supplied ?.

Martin Brown wrote:
On 18/12/2020 13:34, Dave Plowman (News) wrote:
In article ,
Martin Brown wrote:
On 18/12/2020 13:15, NY wrote:
"Andrew" wrote in message
...
If they were migrating geese then there could be
some free roasted xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?.
How would they stay apart during high winds, which
are expected in that part of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

That was my thought: if the starlings landing and taking off stretch and
swing the wires so much that they touch, even in cold weather when the
heat hasn't made them expand, then a gale could do the same. The wires
need to be tightened.

It was a hell of a lot of starlings on each wire. Individually they may
not weigh much but on those numbers and all acting in synchrony they
must be well beyond normal design tolerances.

Our local mains in the village is three phase aluminium core wrapped
around a steel hawser. It proved strong enough to support most of the
weight of a tree. The recoil when the tree was cut free was spectacular!

All the poles in the village are now banana shaped with "do not climb"
warning stickers on them.

Would insulating them to prevent this actually cost a lot?

Not really.

Many of the distribution single phase wires in villages start out with
insulation on them but after a few decades it perishes and hangs down in
strips arcing and sparking in the rain when it touches another phase.
Sometimes it was bad enough to trip out the circuit breaker.

Ours used to be like that before they replaced it with the modern
composite aluminium cable with the internal steel hawser.


I dont know all boards did it but SWEB which covered the area where I grew
had insulation on some
11Kv cables where they crossed roads,maybe 33Kv ones as well but I didnt
pass under any of those
while cycling to school. That would be mid to late 1960s and I can
remember when a new line was installed the plastic insulation stood out
because it was green covered.
Also at that time a lot of the pylons of the original 132kv grid.used to
have a safety net of wires
where the lines crossed a road or railway ,that died out some time ago
possibly some of that network was transferred from the CEGB to the regional
boards, occasionally you still see the brackets for them on and old pylon
like this one .

https://goo.gl/maps/FmTkg6u6y27m1kXe9

GH

In article , Marland
wrote:
Martin Brown wrote:
On 18/12/2020 13:34, Dave Plowman (News) wrote:
In article , Martin Brown
wrote:
On 18/12/2020 13:15, NY wrote:
"Andrew" wrote in message
...
If they were migrating geese then there could be some free roasted
xmas dinners :-).

Perhaps those 11Kv lines are a bit too 'saggy' though ?. How would
they stay apart during high winds, which are expected in that part
of the country ?..

https://www.bbc.co.uk/news/uk-scotla...ntral-55334891

That was my thought: if the starlings landing and taking off stretch
and swing the wires so much that they touch, even in cold weather
when the heat hasn't made them expand, then a gale could do the
same. The wires need to be tightened.

It was a hell of a lot of starlings on each wire. Individually they
may not weigh much but on those numbers and all acting in synchrony
they must be well beyond normal design tolerances.

Our local mains in the village is three phase aluminium core wrapped
around a steel hawser. It proved strong enough to support most of the
weight of a tree. The recoil when the tree was cut free was
spectacular!

All the poles in the village are now banana shaped with "do not
climb" warning stickers on them.

Would insulating them to prevent this actually cost a lot?

Not really.

Many of the distribution single phase wires in villages start out with
insulation on them but after a few decades it perishes and hangs down
in strips arcing and sparking in the rain when it touches another
phase. Sometimes it was bad enough to trip out the circuit breaker.

Ours used to be like that before they replaced it with the modern
composite aluminium cable with the internal steel hawser.


I don‘t know all boards did it but SWEB which covered the area where I
grew had insulation on some 11Kv cables where they crossed roads,maybe
33Kv ones as well but I didn‘t pass under any of those while cycling to
school. That would be mid to late 1960‘s and I can remember when a new
line was installed the plastic insulation stood out because it was green
covered. Also at that time a lot of the pylons of the original 132kv
grid.used to have a safety net of wires where the lines crossed a road
or railway ,that died out some time ago possibly some of that network was
transferred from the CEGB to the regional boards, occasionally you still
see the brackets for them on and old pylon like this one .

https://goo.gl/maps/FmTkg6u6y27m1kXe9

GH

Nets were used when cables were being replaced

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle