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June's Pylon of the Month is an absolute cracker that I first came across on Twitter courtesy of @CPF_Photography who then kindly gave permission for me to use it.  It was taken in Birmingham near one of the city's many canals and for more wonderful Birmingham photographs look on the CPF photography website.  Let's deal with Birmingham and canals before we get into the pylons themselves.  A quick google search will reveal claims that Birmingham has more canals than Venice with 35 miles of waterways compared to Venice's 26 miles.  It turns out to be true but as the National Community Boats Association points out:

It’s at the heart of England’s canal network and has 35 miles of waterways so it does technically have more than the 26 miles of navigations you’ll find in Venice. But Birmingham is much bigger than Venice, so the density of canals there makes them a much more prominent feature of the city. Also, the canals of Venice are wide, whereas Birmingham’s waterways are narrow.

My elder son is at university in Birmingham and so I've been there quite a few times in the last couple of years, but the canals have yet to feature on my trip itinerary.  That clearly needs to be rectified as soon as possible.

Now to more pylon related issues.  The first thing that struck me when looking at the photograph is the wonderful reflection in the canal of the pylon in the foreground.  More careful inspection revealed that this foreground pylon is a terminator pylon – the end of the line where the cables go down to finish at a sub-station rather than continuing to another pylon. This was quickly followed by noticing that the next two pylons further back look different with two 'ears' rather than a single apex.  The two pylons further back are, however, a different line and I must confess at this point that I'm not entirely clear why they have two 'ears'.  I do know that the thin wire running through the top of more standard pylons is an earth wire designed to protect the pylons from lightning strikes but why two?  I look forward to learning more so that I can cross it off my 'things I still need to know about pylons' list.  Despite all the time I've spent writing about pylons over the years and the fact that I'm a Physics teacher this is still quite a long list. Let me know if you can help to shorten it a little…..

 

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4 responses to “Pylon of the Month – June 2019”

  1. Megan Hicks Avatar

    Absolutely delighted to rediscover Pylon of the Month. On a whim I did a Google search, and here it is. The original incarnation of Pylon of the Month was one of the first quirky blogs (was it called a ‘blog’ then?) that I and a fellow museum curator followed way, way back when we first had access to the Internet. And what beautiful images and great information you are sharing. This Birmingham photograph is stunning.
    Best wishes
    Megan
    Sydney, Australia

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  2. K A Mosedale Avatar
    K A Mosedale

    I’m glad to welcome you back to the blog in its new reincarnation!

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  3. Scott Avatar
    Scott

    I am a transmission line engineer in the United States and I enjoy seeing the unique pictures and designs from across the world. As for your question about the top wires (we typically call them static wires), you are correct in that they are grounded to protect the circuit from lightning strikes. In design, we try to keep the conductors underneath the static wires within a certain angle range. Thus, wide structures can require two static wires rather than one.

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  4. Daniel Beardsmore Avatar

    The question about twin earthwires is still a mystery. This practice was formalised in the CEB L132 specification of 1940, yet of the three known CEB L132 types (Blaw Knox PL16, Eve 0.4 and Eve 0.172), only the Blaw Knox type used it, and it fell out of favour.
    Officially, the first mile out from the substation was meant to be twin earthwire for enhanced protection, which is what you see. What happens if lightning strikes a phase conductor before or after the one mile mark? Why are there 132 kV lines with no earthwire at all (including all modern Trident wood pole lines)? How do 11 and 33 kV wood pole lines cope without an earthwire?
    Modern practice is to use a smaller arc gap on the arcing horns for the first mile, seemingly to try to force a flashover to earth. There are also lightning protection arrangements at substations that seem to be arranged similarly, to induce lightning to flash over.
    So far, I have never seen any definitive information about this!

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