Technology

Pylon of the Month - August 2017

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 This month we have a Scottish pylon from Loch Errochty, a man made freshwater in Perth and Kinross.  The pylons are on the Beauly to Denny power line which brings power from renewable sources in the north of Scotland to consumers further south.  It was (and remains) very controversial and the Herald Scotland reported back in 2015 that 'Its impact on the Highland landscape was compared to taking a razor blade to a Rembrandt'.  Those who planned and built it insist that it is essential if Scotland is to meet national renewable energy targets.

You can see a more zoomed out picture below.

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A few factoids from the BBC

  • The line is 137 miles long and supported by 615 pylons which run through some of the country's most inaccessible terrain.
  • The project supported more than 2,000 jobs over seven years
  • But it attracted about 20,000 objections
  • It is the longest transmission line to be built in the UK in recent times
  • Its highest point is the Corrieyairack Pass at 2,526 feet

As soon as I saw the picture (which was sent in by a fan of the website), my thoughts went to a 2009 article in the Guardian by Jonathan Glancey entitled 'The Gaunt Skeletal Beauty of Pylons'.  I wrote about it back in 2009 and it was the article that first introduced me to the Pylon Poets and Stephen Spender's poem about pylons. Rather pleasingly, the post is still number three on Google if you search on 'pylon poets' which explains why I still get a fair bit of traffic on the blog from a post that is eight years old.  Anyway, I still think that there is a kind of beauty that pylons bring to a landscape.  So did Barbara Hepworth according to this very scholarly article from the Amodern website

Likewise, the sculptor Barbara Hepworth drew inspiration from the sight of “pylons in lovely juxtaposition with springy turf and trees of every stature” seen from the window of an electric train.

The same source makes it clear that there was plenty of opposition to the pylons that the construction of the National Grid in the 1920s and 30s brought:

For others – including Rudyard Kipling, John Maynard Keynes and John Galsworthy, co-signatories of a letter to the editor of The Times – the erection of “steel masts” carrying “high-tension wires” over the Sussex Downs amounted to nothing less than “the permanent disfigurement of a familiar feature of the English landscape.”

But Reginald Blomfield, the man who oversaw the design of the new National Grid pylons was having none of it in a letter to the times:

Anyone who has seen these strange masts and lines striding across the country, ignoring all obstacles in their strenuous march, can realise without a great effort of imagination that [they] have an element of romance of their own. The wise man does not tilt at windmills – one may not like it, but the world moves on.

I'll finish with a 1933 poem by Stanley Snaith discussed extensively in the Amodern article.

Over the tree’d upland evenly striding,

One after one they lift their serious shapes

That ring with light. The statement of their steel

Contradicts nature’s softer architecture.

Earth will not accept them as it accepts

A wall, a plough, a church so coloured of earth

It might be some experiment of the soil’s.

Yet are they outposts of the trekking future.

Into the thatch-hung consciousness of hamlets

They blaze new thoughts, new habits.

                                                                              Traditions

Are being trod down like flowers dropped by children.

Already that farm boy striding and throwing seed

In the shoulder-hinged half-circle Millet knew,

Looks grey with antiquity as his dead forbears,

A half familiar figure out of the Georgics,

Unheeded by these new-world, rational towers.


Pylon of the Month - June 2017

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The month of May passed by without a pylon and so summer is now here rather than 'icumen in'.  This month's pylon, however, is looking back to a day in the Alps earlier in the year when a fan of the website took time out to take this picture of a mountain pylon.  The angle of the transmission lines leaving the pylon is pretty impressive, but sadly for pylon fans everywhere I couldn't find any technical details of maximum permissible angles or the engineering challenges of building pylons in mountainous areas.

 The email by which the picture arrived was pithy and to the point:

At Plan des Queux near Pointe de Daillant in French Alps. Height: 2150m. 

It also showed evidence that this pylon fan had been willing to go the extra mile (metaphorically if not literally):

Accessed on foot.

I couldn't track down the exact location on a map, but a quick look into electricity in the French Alps led to a story that I found impossible to ignore.  

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So if you're a pylon fan and a cheese connoisseur on a skiing holiday next year then surely you won't be able to resist popping to Albertville.  If you do and there pylons on view please do send me a picture!

 

 


Pylon of the Month - February 2017

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Happy New Year (somewhat belatedly) to pylon fans everywhere!  

Despite the relatively mild and wet weather as I write this month's post, February seemed the right month for this fantastic picture to feature as Pylon of the Month.  It was taken in West Yorkshire just outside Ripponden by Adrian Jackson.  As he pointed out in the email he sent in with the picture:

The photo has only been treated to change exposure and colour balance, no pylons have been added. There are actually two lines of pylons which both turn through ninety degrees.

Now for some serious pylon geekery.  Talk of turning through ninety degrees above prompts me to talk about the difference between pylons where the transmission line is running in a straight line as opposed to when there is a change in direction.  In a straight line run, the line is suspended from the pylon by vertical insulators (see the second and third pylons going down the hill above).  However, when there is a change of direction (like in the pylon in the foreground above) the insulators are horizontal and the pylon is known as a tension pylon.  More from the National Grid on a page talking about the new T-pylons:

In a perfect world electricity transmission lines would run as straight as possible, but natural barriers, such as hills, rivers and roads, have to be circumvented or crossed and land rights issues can often require a route to turn a corner.  This places a lot of lateral strain on a pylon, to the side where the line turns, and so the suspension design needs to be supplemented so pylons can resist being pulled to one side.............. the extra strength required will mean that the wires will not be able to be suspended vertically from insulators, but will instead need to be held in place more securely by horizontal insulators tied to the pylon itself – hence the term, tension pylon.

You might also notice above that there are loops of wire dangling from the tension pylon that you don't see on pylons where the line is running straight.  These loops are known as 'jumper loops' and again from National Grid:

Due to the lines being tied to the structure itself by insulators, we have to provide a path for the electricity to continue to flow. So, we use ‘jumper loops’, which are short sections of electrical wire connected to the main (live and earth) wires just before they tie to the insulators, terminating the line to the cross arm. The jumper loops are designed to ensure the live wire does not touch the earthed structure.

What a great way to start 2017. A fabulous pylon picture in a Yorkshire landscape and technical pylon talk.  To make February even better, make sure that you get along to the Wellcome institute for their "Electricity: The Spark of Life" exhibition which opens on 23rd February and runs until 25th June.  If you team that up with watching 'Amongst Giants' a film about Yorkshire pylon painters starring Pete Postlethwaite then you'll really have ticked all the boxes.

 


Pylon of the Month - April 2015

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This has been a very busy month on the pylon front.  As well as making it onto the BBC website (Meet the Pylon Spotters) along with Flash who runs the Pylon Appreciation Society, I have done several interviews on local BBC radio stations about pylons.  The reason for this is that the six new T pylons (which I talked about back in November 2011) have been at installed at the National Grid training centre in Nottinghamshire and for a couple of days the UK went pylon mad, setting a new daily record of 4265 hits on Pylon of the Month.

I could have let all this publicity go to my head, but after considering featuring the new T pylon for April I have decided to stay true to the many fans who have sent in pylon pictures.  When I get a 'real' picture (rather than one from the internet) of the new T pylons I'l definitely use it, but until then it is business as usual.  So this month's picture was taken in Edinburgh and sent in with the following message:

Our colleague............is very keen on your blog ‘Pylon of the month’ we took these photos out of our office windows earlier today – it would make his day/week/month if they could be included in your blog...... 

The window in question seems to be at the Milton Road Campus of Edinburgh College, which rather fittingly offers Electrical Engineering amongst many other courses.  With any luck, the news feed on their home page might soon be announcing the exciting news about Pylon of the Month featuring a nearby pylon.  It might even get people at the college debating whether they prefer the old lattice pylons as featured above or the new T pylons.  Flash Bristow has no doubts that 'These new electricity pylons will make Britain a duller place' although I'm not so sure.  They won't be replacing existing pylons and even new pylon lines will have the option of using the T pylons or not, so with variety being the spice of life perhaps it will enhance the pylon offering in the UK.  For lots on this and for more regular pylon action go to Twitter and @pylonofthemonth.  


Pylon of the Month - January 2015

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Happy New Year to pylon fans everywhere!

This month's pylon(s) comes from South Africa and is yet another another addition to the 'pylon pictures taken out of the window of a moving vehicle' category.  I took it in December whilst on a family holiday in South Africa and the pylons can be found near Stellenbosch, just after you join the N2 to head East on the fabulous Garden Route.   

A bit of research tells me that South Africa currently relies heavily on coal for energy production (88% according to a graphic in the Observer's January Tech Monthly, but 77% according to Wikipedia) largely because there is a lot of coal in the norh of the country.  It also revealed that in June 2014 Johannesburg suffered power disruption due to:

......the theft of 88kV electricity pylons between the Nirvana and Nancefield substations.  City Power electricians are currently in the areas and have started the project to replace the stolen pylons and also to repair those that can be replaced....

I had to follow up this story, but my visions of whole pylons being carted away on the back of a truck were dashed when I read that:

cross members of pylons were stolen, causing the bolts to loosen at the base of a pylon, resulting in the collapse of one of them.  The next pylon on the circuit also collapsed as a result of the strain.

I'll sign off there for now, but with plenty of pictures lined up for 2015, make sure that you come back regularly for more pylon action.

 


Pylon of the Month - June 2013

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This month's pylon comes from Kennington just outside Oxford and for reasons that will become obvious, I took it myself very recently.  It is very easy to find, being a few hundred metres from Sandford Lock on the Thames on the Sustrans cycle path from Abingdon to Oxford.  But the main reason I chose this pylon is because I could get a close up of something attached to the wires just before cables join the tower. Once you have seen the in the picture below, you will see them everywhere, but unless you are a real pylon spotter you have probably never noticed them before.

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The objects in question are the dumbell shaped objects and they are known as Stockbridge dampers or dog bone dampers because of their shape.  They perform a vital role in preventing damage to the cables and in order to explain how they work, it is time for a little bit of theory.  Some readers of the blog might know that I am a Physics teacher, but I will try to stop myself from getting too carried away.  I'll also try to get the physics right without over complicating or over simplyfying things, which might not be as easy as it sounds.

The basic problem is that wind blowing on the cables can make them vibrate, or more specifically vortex shedding on the leeward side leads to this undesirable effect.  It can do this in a number of ways, but one of the modes of oscillation is called Aeolion vibration or flutter.  The vibration has an amplitude of a few millimetres to a few centimetres (this is how far the cable moves up and down) and a frequency of anywhere between 3 - 150 Hertz (vibrations per second).  This kind of effect, where some a driving force (in this case the wind) causes something to vibrate at its natural frequency is very common.  If you have ever seen or heard a washing maching as the drum speeds up in the spin cycle, you might have noticed that there is at least one particular speed where the washing machine shakes violently.  The problems with the Millenium Bridge in London when it wobbled as people walked across it just after opening were also a variation on this theme. But the most dramatic example involving the wind is probably the collapse of the Tacoma Narrows Bridge and if you haven't seen a video of the wind induced oscillations, now would be a good time to tick that off your 'things to do before you die' list.  But back to pylons, because as you will know if you have ever bent a paperclip a few times, repeated stress can lead lead to the metal failing and in the case of pylons on a windy day (or more likely the cumulative effect of many windy days) this could lead to strands of the overhead power lines breaking.

So how do Stockbridge dampers help?  In very simple terms, instead of the wire vibrating the masses on the end of the damper vibrate instead and so the cable vibrations are 'damped' or reduced in amplitude. The idea was invented by George H. Stocbridge in the 1920s and originally consisted of two small blocks of concrete on the end of a piece of metal wire.  

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The original US patent is an interesting read if you want to know more, but in the words of the inventor:

My invention relates to means for preventing objectionable vibration in suspended cables, such as are used in electrical transmission lines and the like.....

The wikipedia page on Stockbridge dampers also has more information, but there is much that I would like to find out about how they are used.  In particular, are all dampers the same or do they vary depending upon the specification of the cable?  If you work for National Grid and know the answer please do get in touch and if you had a real life Stockbridge damper that I could use when teaching about resonance in my Physics lessons, I would be extremely grateful.

If this was all a bit too much information for the casual visitor to the website just looking for a new pylon picture then I can only apologise.  I hope that you can at least spot a few Stockbridge dampers on your pylon travels and if nothing else, it might make you realise that there is more to pylons than meets the eye.


Pylon of the Month - March 2012

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This month's pylon comes from Afganistan and at a height of around 3800m above sea level, I'm pretty certain that the pylon in the background of the picture is the highest pylon to feature on Pylon of the Month. Are there any higher pylons anywhere in the world? Answers in an e-mail to Pylon of the Month please.  It is located along the Pul-e-Khumri to Kabul transmission line, where it runs over the Salang pass which links Northern Afghanistan to Southern Afghanistan and Pakistan.  Also along this line is the Chimtala substation. There is lots of information about this substation here, but a direct quote may fill in a few details for those without the time to read more deeply:

A terminal link of Afghanistan's North East Power System (NEPS), the Chimtala substation is an infrastructure project funded by India as part of its assistance package to the Afghanistan Government. Located near Afghanistan's capital Kabul, the substation imports power from Uzbekistan to Kabul.

From my perspective as a physicist, there are more exciting details about how the electricity is transmitted using a Double Circuit transmission line. They use the acronym DC for this, but as this also stands for Direct Current (as opposed to Alternating Current or AC), I can see scope for confusion here. I'll put it on my list of things I need to understand more deeply.  So here is the quote:

The 220/110/20kV substation supplies additional power from the 220kV Pul-e-Khumri to Kabul double circuit (DC) transmission line. Passing over the Salang Range at an altitude of 3,800m, the transmission line is 202km long.

So this month, Pylon of the Month has brought you some beautiful mountain scenery, a dash of advanced electrical theory and story of things getting better in a troubled part of the world. How am I going to top that next month?