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Pylons .


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I was wondering how many conductors are used on each circuit and does it vary with voltage? Mostly I see smaller towers with single conductors, but larger ones usually have two or four, and I have just noticed some with three and one run has three on one side and four on the other.

 

The other thing I was wondering about is the number of earth wires on the top - why do some runs split in to two earth wires for a short length?

 

If you want to see how the fibre optic is wrapped round the earth wire there has been a bit of apparatus perched on the earth wire in the middle of a span above Boreham on the GEML for about a week - - might still be there!

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Ah yes

 

All of my favourite pylons, I only really like l6’s so that makes more sense now, if I remember correctly aren’t there 2 different types of l6 or is there just one?

I'm sure I had some info that gave impression there were 4 L6 designs; Balfour Beattie, Blaw Knox, another one plus a CEGB design. I will have to look on pc when i get home to be sure.

Paul

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I was wondering how many conductors are used on each circuit and does it vary with voltage? Mostly I see smaller towers with single conductors, but larger ones usually have two or four, and I have just noticed some with three and one run has three on one side and four on the other.

 

The other thing I was wondering about is the number of earth wires on the top - why do some runs split in to two earth wires for a short length?

 

If you want to see how the fibre optic is wrapped round the earth wire there has been a bit of apparatus perched on the earth wire in the middle of a span above Boreham on the GEML for about a week - - might still be there!

The number of conductors depends on the operating voltage and line capacity requirements but as a general rule the following applies:

 

Up to 132kV:

* Non standard small towers (that mostly pre-date the creation of the National Grid in 1930s) = single conductors upto 66kV

* PL series towers (like Hornby kit) = single conductors upto max. 132kV for single and double circuits.

* L4 the 1970s replacements for PL double towers = single

 

132 to 275kV:

* L2 Supergrid towers introduced 1950s originally 275 most now 400kV = double - it is rare to see L2 towers on single often used to replace other towers

* L3 which look like a smaller version of the L2 were mostly doubles but a lot are being restrung with singles. Same applies to L3C with long middle crossarms

* L7 same as L3 often double when built some now singles

* L8 used to replace or supplement L2 and hence only doubles

* L6 most were four or quad conductors from new in 1960s a lot now are three/tri or even doubles.

 

As conductor and insulator design and technology has improved there has been a big push to replace the quad conductors with doubles that will take the same load. Sometimes they replace quads with tri conductors. It isn't uncommon to see one line go from say quads to doubles especially where the line and towers change from L6 to L2 but the circuit is a through one.

Paul

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Thought this photo, taken by my Dad at a Road Race in Ugley, Essex back in May 1966 might be of interest. The power line in the background was fairly recent then, probably just two or three years old at a guess.

 

post-1877-0-24615500-1537885028_thumb.jpg

 

Another view of the same line, but to the left of the first picture, some eight years later, 1974.

 

post-1877-0-81411900-1537885374_thumb.jpg

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Thought this photo, taken by my Dad at a Road Race in Ugley, Essex back in May 1966 might be of interest. The power line in the background was fairly recent then, probably just two or three years old at a guess.

 

attachicon.gifPowerline1966.jpg

 

Another view of the same line, but to the left of the first picture, some eight years later, 1974.

 

attachicon.gifPowerline1974.jpg

Hi, thanks for sharing, regarding the power lines, is that the one between Pelham and Walton Highway substation’s? Reason being is that Burwell substation is along that line too but I believe the line was upgraded to triple conductors and only one line of insulators on the straight masts in the late 90s early 2000s?

 

Does anyone have any photos of burwell substation in the 70s and 80s?

 

Best regards, Matthew

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the strangest "power lines" ive seen, as in they are something i dont pay attention to but these caught my eye, are in peterborough running parallel with the railway out towards march, they look almost contenental to me, certainly not seen anything like them elsewhere?

 

hopefully this will take you there to do a streetview

 

https://goo.gl/maps/q1HsJoU91D62

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I'm sure I had some info that gave impression there were 4 L6 designs; Balfour Beattie, Blaw Knox, another one plus a CEGB design. I will have to look on pc when i get home to be sure.

Paul

Found my notes there were four designs - Balfour Beatty, B.I.C.C., Blaw Knox and JL Eve according to the PDF a member of the PAS put together some years ago. I have a feeling there might have been a standard CEGB/NG design as well but need to check further.

Paul

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Definitely one for the Pylon spotters - What type?, transmission voltage? and where? (roughly) and don't mean the sheep!

 

attachicon.gifIMG_0223b.jpg

 

attachicon.gifIMG_0225a.jpg

 

attachicon.gifIMG_0225b.jpg

I will guess with the recently doubled Beauly to Dounreay L3 line? If it is this line then it was originally part double circuit for the first few miles out from Beauly after which it was single circuit using one side of the towers the remainder of the way.

Paul

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the strangest "power lines" ive seen, as in they are something i dont pay attention to but these caught my eye, are in peterborough running parallel with the railway out towards march, they look almost contenental to me, certainly not seen anything like them elsewhere?

 

hopefully this will take you there to do a streetview

 

https://goo.gl/maps/q1HsJoU91D62

Hi Jim, yes they are odd looking things - there are some similar ones on the east side of the M6 as you pass Castle Bromwich/Washwood Heath where the large L6 towers run parallel to the motorway. I think there are some more of these single pole stick things around Cambridge as well IIRC

Paul

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  • RMweb Gold

the strangest "power lines" ive seen, as in they are something i dont pay attention to but these caught my eye, are in peterborough running parallel with the railway out towards march, they look almost contenental to me, certainly not seen anything like them elsewhere?

 

hopefully this will take you there to do a streetview

 

https://goo.gl/maps/q1HsJoU91D62

I've not travelled that line for the best part of 30 years but could immediately visualise the ones you meant!

 

Andi

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Hi Jim, yes they are odd looking things - there are some similar ones on the east side of the M6 as you pass Castle Bromwich/Washwood Heath where the large L6 towers run parallel to the motorway. I think there are some more of these single pole stick things around Cambridge as well IIRC

Paul

There are some on Cambridge, at the science park. They weren’t originally there when the Cambridge to st ives railway was in operation, I believe they were added when the science park opened.

 

Best regards, Matthew

 

Ps I do have photos of these, I will find them

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I will guess with the recently doubled Beauly to Dounreay L3 line? If it is this line then it was originally part double circuit for the first few miles out from Beauly after which it was single circuit using one side of the towers the remainder of the way.

Paul

 

 

Spot on with your guess Paul - the 275kV transmission line that runs in between Rogart Station and The Mound....

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I presume Paul these codes represent the tower (244)? and the separate circuits BT 1 & BNG 2

Yes the 244 would be the tower number and BT1 and BNG2 the circuits. This applies to cicuits roughly to the north side of the Forth on the east coast side of Scotland.

The central and southern Scottish lines have a route code only as do English and Welsh lines but one circuit may span several different codes. A local example to me is the 400kV circuit from Stalybridge to Macclesfield this starts on route ZZC then becomes YV where the latter tees into ZZC near Stockport.

Cheers Paul

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