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UK Electrical Transmission System



Jan 1, 1970
I am doing some research on the UK Electrical national gird system and
looking for lots of info.

I am after stuff like national layout, means of control and power
regulation, safety issues/procedures, transmission voltages and the like.

Much appricated any info or web links.

Thanks in advance,


Don Kelly

Jan 1, 1970
No reason for it most of it to be sensitive- much of it is in textbooks or
IEE journals and terrorists can surely recognise a major substation when
they see it. I would suggest that Grahame ask the utility directly and
would likely get more information than he can digest. .


Jan 1, 1970
Hey its not my fault you live in a paranoid country.

How can you judge what the UK can or cannot put into the public domain?

It's that sort of attitude that has got the US into the state into which it
finds itself today.

Or are you embarrassed because you told the original poster "don't hold your


Jan 1, 1970
Charlie Perrin said:
One source mentioned 200KV.

I also found one note that said it wasn't in operation (at least the
1961-era ABB system).

Big thanks for all this info. Most useful.

No thanks to those people who think my surname must be "Bin Laden".


Andrew Gabriel

Jan 1, 1970
I seem to remember that the original cable was replaced by a new one
at some point, but I don't know for certain if that one is still in

It certainly is. Political climate in UK prevents building any
more nuclear power stations, so the French build them for us
all along their North coast, and we buy the electricity from

It was originally installed mainly for the UK to sell electricity
to France, but has actually used almost entirely the other way


Jan 1, 1970
Are you always so discourteous when someone disagrees with you?

No not when anyone disagrees with me, just when they make assumptions
without checking the facts out.
A person with a rifle equipped with a silencer and a telescopic sight can shut
down a substation without being discovered. A small group can shut
down multiple substations and put a major city in the dark for an
extended period of time. Such a map tells them where to deploy their

If any one was that intent, they could buy Ordinance Survey maps of any area
to find such detail


Jan 1, 1970
I don't disagree that the US is paranoid, having never had exposure to
Hitler, Napoleon, the Armada, the Vikings, the Normans, etc. Given
the recent happenings in Ossetia, that paranoia might be prudent.
Like when Luke Skywalker said to Yoda that he wasn't scared, Yoda
replied, "You should be."

But the US was exposed to Hitler. U-Boats struck tankers from New
York to Cape Hattaras and the Gulf of Mexico. German Spies were
landed on long Island. Also, many say the Vikings did invade America
as well...



Jan 1, 1970
Distribution is normally at 11, 33 or 66 kV. 22kV. is sometimes used,
but not often; it is more common in mainland Europe.
I thought it was 22kV in UK and 20kV in mainland Europe although I
think there is some 20kV in Yorkshire.

I think the reason that 22kV was selected is that it was the highest
voltage (at that time) that a belted paper insulated cable could be
designed for. Such cables failed at 33kV and were successful only
when filled with oil or dry nitrogen. These 22kV cables would have
been originally for subtransmission rather than 'final' high voltage


Jan 1, 1970
Chris Johnston said:
Hardly the same level of detail, but that's not my point. My point is
that exposing detail of that level compromises security. A person
with a rifle equipped with a silencer and a telescopic sight can shut
down a substation without being discovered. A small group can shut
down multiple substations and put a major city in the dark for an
extended period of time. Such a map tells them where to deploy their

Trying to hide such information about things that are in plain site is a
waste of time. Might as well try to hide a cooling tower that's visible
from 10 miles away.

Buy a topographical map (available many places) and it shows power lines and
substations. Download a satellite photo and you can pick out the power
lines. Drive around in your car on the week ends and you'll stumble across

Terrorists are not stupid. If they want to find information about power
lines or substations, there are easily half a dozen sources they could use
to find it. Paranoia about reporting 'suspicious' activity in recreational
marinas, 'hiding' information about things that are in plain site, it's all
got to stop. The more paranoid we act, the more the terrorists win.


Graham Gould

Jan 1, 1970
WHen Iw as working for a REC about 15 years ago there was a bit of a problem
from the society for the two headed sheep ( somthin like that anyway) They
tried to disrupt the UK electical network by cutting down a 400kV tower near
to Dungeness. 25 hacksaw blades later and they left exhauseted!!! BUt the
point is that despite the fact that power is an easy target there is not
much evidence worldwide that this is a potential target. Unless they took
out a lot of circuits they would not have much effect. Crash a few lorrieson
the M25 and M1 is a whole lot easier to get top ratings in the press!

It dosnt need us to say how easys or hard it is to disrupt the systems. But
its got to be more that a man with a gun or a hacksaw to have any worthwhile
effect. The evidence is clear its not done a lot! I think we are a bit lucky
as it is fairly easy to do but would not get much headline news unless it
was a big concerted effort.

Cable laying contractors and builders ahev a far more likely chance of
making thigns happen!

As for the network diagram then it is available in the public domain ( the
transmisison entwork is even on the OS maps and it is fairly easy to walk
routes to see where the towers go and the cables start and end.
There is not a lot of 400KV underground and not too much 132kV although
there is a lot around city centres

Vltages inthe UK are
275 usually to 400kV spec

66kV ( not a lot but some older stuff)

33kV the main distribution voltage
22kV not a lot again a legacy system

11kV the most prolific
6.6 quite a bit ( often out of phase with itself)
3.5/ 2/ 2.2 and other odd bits
then the final is 415 (ish) and 240 (ish)

I saw the last DC rectifier in use int he South East when I started my
training in 1972 so I doubt if there is much of that left now!!!!

Same random not too accurate summaries! These are sumamries so dont pick me
up on them if they are incomplete but if I have it wrong then 20 years of
lecturing has gone out the woindow!!!!!

The DC link is 2 dc circuits that allow power flow (cant remember the
voltage) (france to the UK nrormally ) of around 2GW MD its DC to help
avoid voltage control problems and help to tie the two systems together
without having them have to haev the same frequency. It also limits fault
current flow.

voltage control is acheived by generators and static and rotating
compensators etc to provide the VAR control and tap changers manage the
final delivery of voltage.

cables and lines each have a different effect on voltage control

Bored now so going to bed!

John C

Jan 1, 1970
As a Power engineer on Standby and still operational I have read the last
several posts with much merriement.

seen it. Usually a little brat with an air rifle making sparks....

Chain Man..
thrown over the line

Fire man.

Under the cable boxes in the substations

all guarenteed to switch of a large area for several hours!!!

have fun!!!!


the two headed sheep shagger society is still in operation!!!!!