Cables Earthed on Pylon

[charles]

Hi guys,

Can anyone explain why the high voltage cables on this pylon appear to be earthed at the pylon? It's on the north side of the M60 at Stockport. 53°24'24.3"N 2°11'21.7"W
See attached.

Regards,

Charles

 

[James]

I can't see the bond to pylon myself but I believe that at times when they are working on cables (power off) they sometimes bond them to earth to prevent static build up

 

[charles]

Hi James, the cables have been like that for well over 20 years.

 

[snowhead]

If the farside left cables are earthed to the pylon it would be because they are not in use.
The farside right cables look to be connected across the the nearside right.

 

[R-fur]

James is correct, circuits are earthed when people are working on them to protect against induced voltages and isolation failures.
What the picture shows however is the jumpers bolted to the steel tower, this is done on out of use circuits.
Incidentally a linesman was killed in Glasgow about 20 years ago while working on an isolated circuit, induced voltages from the other circuit on the towers and a failure of other safety systems did him.

 

[James]

I see what you mean now,
it looks like the cables are joined far right to near right to near left.
the far left hand cable looks as though it is bonded to pylon.
this is repeated on all 3 levels.

I can only guess that there is a problem with a cable or insulator on the section that is bonded to pylon. it has been taken out of service.

could be that they don't need the capacity anymore so it has not been repaired.
they are phasing out coal powered generation, it could even be that the cables go to a generation plant that has had its output reduced.

 

[charles]

If the cables have been installed when the pylons were erected what's the point of not using them?

 

[Andy78]

What do the DNO have to say ?

 

[snowhead]

If the cables have been installed when the pylons were erected what's the point of not using them?

They may have intended to use them but more likely it's to balance the strain on the pylons.

Looking from the other side they are linked.

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[StephenRowley]

It's not just induced current there are also circulating currents.

 

[littlespark]

Do not try to repair this yourself. Get an electrician in

Sorry, couldn’t resist

 

[StephenRowley]

Looks like a t circuit also judging by the length of those insulators that 275kv kit so national grid stuff rather than dno

 

[Strima]

If the cables have been installed when the pylons were erected what's the point of not using them?

They stop the pylons from falling over. It may well have been planned for future capacity that never materialised.

 

[James]

They stop the pylons from falling over. It may well have been planned for future capacity that never materialised.

That row of cables sits between a large sub station and a hydroelectric station if you look on google

 

[StephenRowley]

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openinframap.org

400kv so it's NG stuff