HV pylons - what are these?

[RF Lighting]

There is a pylon at the side of the road at the traffic lights at the end of my village.

I have often sat there waiting for the lights to change staring at this pylon.

The one thing I'm curious about is there is a little doofer attatched to each of the lines just before the insulators.

What are they and what is their purpose?

 

[westie101]

Vibration dampers, in certain conditions the cables can vibrate, these are to prevent those running away with catastrophic results as in the Tacoma Narrows Bridge

 

[mfarrow]

Looks like a damper:

http://www.nationalgrid.com/NR/rdon...head_Line_Construction_Presentation_FINAL.pdf

 

[RF Lighting]

Interesting. Do you know how they work?

 

[westie101]

Article here

http://en.wikipedia.org/wiki/Stockbridge_damper

 

[mfarrow]

and a techy drawing...

Railway overhead lines sometimes have a much simpler bias weight in the tail wire before the anchor position, if the tail wire is particularly long. They're oblong shaped and I'm not sure there's anything special about the construction. The spans are a lot shorter than grid wiring anyway.

 

[RF Lighting]

How interesting! I shall think of this thread every time I'm sat at the traffic lights now!

 

[westie101]

There is actually a Pylon Spotters Group if you are really interested!!

 

[RF Lighting]

I'm not that bad!

 

[bernardgreen]

Reminds of the Beach Boys

Im pickin up good vibrations
Shes giving me excitations
Im pickin up good vibrations
(oom bop bop good vibrations)

 

[Lectrician]

There was an episode of "How Do They Do That" which showed these dampers being changed just prior to some bad weather coming in. They really over dramatised how essential it was they were replaced before the weather hit.

Two men dropped on the middle of the line from a copter, and scooting up the lines to them, similar to the infamous youtube clip.

 

[ban-all-sheds]

Helicopters?

Wimps.

 

[maltaron]

Interesting to see the different access methods. The main transmitter mast for Cornwall is on top of the hill close to my place and you often see a little cabin which runs up a guy line to the maintenance platform, and that's up-a-depth as well.