How much current flows through pylons?

Graham Nye submitted this idea :

Either, both or even direct from the supply.

One series of 3.3Kv sets I installed in the 1970's was Ambergate PS, but that had its own local sub stations, two ss as I recall.

Someone is being slightly economical with the truth at the emfs.info site. There are 400kV overhead circuits in the UK rated at around 3600MVA short term post fault so that equates to around 5000A.

Not only is 3.3kV used in the UK, but 2kV, 3.5kV and 6.6kV are also used. In some areas 66kV is also used alongside 33kV, the 66kV being run in some cases on wooden poles.

5.6.1 6.6kV Networks Where 6.6kV assets are to be replaced, 11kV rated plant, switchgear and cables shall be used. All new or replacement transformers used on the 6.6kV system should be dual ratio. Every endeavour should be made to remove 6.6kV rated assets as part of any major reinforcement scheme that either involves the assets directly, or offers the potential to decommission them as part of an associated scheme. Each case will ultimately be considered on its merits and the costs involved will be subject to formal approval as part of the capital authorisation procedure.

On Mon, 20 Mar 2017 09:35:29 +0000, The Other Mike

Plus this, page 4

WPD West Midlands also has extensive 66kV networks. These networks cover large rural areas, including the north Cotswolds, Worcestershire, Herefordshire and the Welsh Marches. Networks at this voltage provide economic and reliable rural systems, permitting long feeding distances and being of robust construction. However, some parts of the 66kV network are ageing and may require replacement over the next 10 years. WPD would consider reinforcement at the 66kV voltage level or conversion to 132/11kV transformation depending on the solution offering the optimum technical and economic value.

Map here of the distribution grid in that area as it is now with colour codes for the various voltages etc.

No mention of 3.3kV , what ever you worked on isn't in place any more or wasn't part of the distribution network. Have to say that as you were unaware that the vast majority of 11kV and 33kV overhead lines in the UK are carried on wooden poles I'm not how much credence we can put on your claim as indicated by "Are you sure it is 11Kv - more likely it will be 3.3Kv." The general opinion on here is that as far as distribution networks are concerned you are wrong and even if there has been the odd bit of non std that only you seem to know about it certainly isn't enough to justify your claim of "more likely".

G.Harman

No. Were used. Once. Not any more.

In

Has been used. No longer

Oh FFS you yet again show you really are a clueless wanker on this and many other things you claim to be 'an expert' on, one thing for sure is you clearly have zero experience in the field of power engineering.

I could walk a couple of hundred yards and take a photo of a sign on the front of a 3.3kV/415v substation, but it's pissing it down and I simply cannot be arsed and in any case you'd probably claim it had been photoshopped or was an image from Victorian times. There is plenty of 66kV single circuit on wooden poles and on pylons too.

Underground can be 3.3kV but not to my knowledge as an overhead, the choices there are 240v/415v 11kV 33kV 66kV and 132kV (for UK distribution networks)

Any other oddball voltages will be underground or as on site supplies. Power stations for instance often have 11kV, 3.3kV and 415v switchboards, steel rolling mills and chemical works have commonly been supplied at 275kV or 400kV transformed down to various combinations of 33kV, 11kV, 6.6kV, 3.3kV and 415v for use around the site.

The Natural Philosopher explained on 20/03/2017 :

Were used, suggests were installed. Once installed they are there until replaced - which rather suggests I was correct in the matter of the

on 20/03/2017, snipped-for-privacy@yahoo.co.uk supposed :

Who suggested it was part of the general distribution network?

Not in place? I very much doubt that, the project was a major and very expensive project, a show project.

I said the site had (from memory) possibly two transformers on site, to feed the site. The run from the transformers was a matter of maybe

Harry you'd be better off arguing with a three week old dead badger, you'd get a more coherent and accurate reply on subjects like this than from TNP. 3.3kV has IME always been an underground voltage in the UK, with indoor switchgear.

That particular project you worked may not have been but you cannot get away from that you interjected on this post from NY :

with "Are you sure it is 11Kv - more likely it will be 3.3Kv." So it looks very much like that you started your contribitions to this thread by commenting on the distribution network and only later invoked your experience of one particular project by suggesting it's rare use of 3.3kV = more likely.

G.Harman

The original title of the thread The person who claimed that overhead poles ran 'at 3.3kV'

Thats all fair enough but the mistake was to claim that was a standard grid voltage used in transmission. It isn't. And I am not sure it ever was except in one or two legacy districts.

Proof by assertion?

I can find no mention of 3.3KV grid ANYWHERE at all.

It's used primarily for motors and as an intermediate voltage in power stations. Never for any distance transmission.

i.e. NOT as part of the grid.

Exactly. I've lived all out in the sticks where everything is up a pole and I talk to all the engineers who fixed the broken stuff because I am an electrical engineer and I am interested.

I have never ever even *heard* of 3.3Kv as part of a grid system. Inside a factory or power station yes. Out on poles - never.

That's short term. Presumably the above link is continuous capacity.

The Natural Philosopher explained :

However the subject under discussion moved away from what everyone would understand to be the grid, to local distribution. It was on the subject of local distribution that I responded.

Sorry but local distribution at 11kv is still part of the grid. Arguably even the 240v feed from the last mile substation is still part of the grid.

They just moved the nominal voltage and tweaked the % +/- to pretty much maintain the same "legal" range. Nothing if anything actually changed. New supplies might aim for 230 more than 240.

Its the UPS clicking that normally alerts me to the problem. B-)

History: When we moved in we'd get through incandescant light bulbs at about 1/month. Then I bought the UPS plugged it in and it went straight into voltage reduction mode. Got out voltmeter, can't remember what it was but close or over 253. Called the DNO, and there was a knock on the door 2 hours later. Agreed my readings, peered at pole transformer, made appointment for a few days later to adjust the tappings. They came back adjusted the tapping as low as it would go and we had something just over 240. Time passed and consumption rate of incandescant light bulbs noticeably dropped.

Didn't offer a voltage monitor? We've had one of those, twice, when I've complained about the overnight voltage when the primary substation is being fed from the 11 kV backup. Last time it happened (up to 256 for several hours over night) they took quite a bit of interest in the graphs I can produce from the logged UPS voltage readings. There was a certain amount of head scratching and going to look at the regulator and the tweak of the 11 kV feed at Little Selkeld. Got a call from some one in an office and ened up emailing daily plots to him.

Of course with the local primary on the main 33 kV feed there isn't a problem and the voltage is very stable at 240 - 245. The voltage monitor was in for a few days after the feed switched back and the follow up call said yes it was high during the 33 kV maintenance period but there wasn't a lot they could do. I've not been aware of any over voltage since then, which either means the primary hasn't been on the back up or it has and they've made some adjustments.

Each time I've reported over voltage they've had a man at the door within hours. Same with outages and speed of supply restoration, either by rerouting or repairs. We have been off supply for 36 hours but there had been an ice storm that brought down the lines in multiple places and the shock of the lines breaking snapped half a dozen or so poles. One of which carried one of the air switches in "our" section so wasn't just a rip the stump out, plant a new pole and restring the lines. But they worked from dawn to dusk for a couple to days to replace it.