Hello
My name is Luke and I am intrested in some some posts on this forum showing photographs of the rural distribution lines/poles in both the UK and Ireland. I am just thinking that when you travel between Southern Ireland (Republic of Ireland) and Northern Ireland can you tell which side of the border you are on by looking at the poles and the designs of the assosiated equipment (pole mounted xformers etc.)?, considering that both parts of Ireland have separate networks (ESB and NIE). Also I have seen photos on this forum of ROI rural distribution but not NI, could anyone upload photos of rural distribution and transmission lines in NI as I am curious as to thier appearence. Do the the rural distrbution and transmission lines in NI use similar design poles/pylons/PMTs to those in Mainland UK considering NI is part of UK and should follow same design standards? Also I know of 3 transmission interconnectors between ESB and NIE, what designs do the pylons on these take, are they to NI or ROI specifications?
Luke

In New zealand you can see quite a few differences between local POCO's.
E.G. The colour of the transformers are different OH & Ground mounted, like green, blue, grey, brownred.
Also the ways the wires are strung at the poles have the odd differences.
Cheers Ray

I'm not 100% sure about NIE standards. For most things they do follow the UK standards, however, you have to realise that NI has never had any direct AC interconnector to the rest of the UK. (The Moyle interconnector is very recent and is DC)

Thus, it has never really been a big issue for NIE to use UK transmission voltages.

However, until very recently, there were also no North-South interconnectors due to the Northern Ireland terrorism problem. The main ESB-NIE interconnectors were targeted by various groups in the 1970s.

So, right through the 1970s/80s and most of the 90s there were no ESB-NIE connections.

ESB's transmission voltages in the republic are:
400kV, 220kV, 110kV and 38kV (sometimes considered distribution)

As far as I'm aware the bulk of the NIE system is 110kV also.

I've also heard that Northern Ireland standardised distribution voltage at 230/400V years ago, perhaps before the UK 240V was picked.

I haven't really had all that much experience of NIE's network components e.g. lines/transformers, but to be honest they don't really look very different to ESB equipment in the Republic.

You can sometimes see where the border is however as all lines (telephone and power) suddenly stop on both sides.

The ESB's pole mounted smaller transformers tended to always (and still are) can-shaped. Similar to what you'd see in the United States in shape/size. You do seem to see more "blocky" looking transformers on NIE poles.

The distribution voltages in the Republic: 10kV, 20kV and 38kV may also be different to the North.

If UK voltages are used, it's more likely that UK style xformers are mounted on poles.

Lyle Dunne or someone in Northern Ireland might be able to enlighten you more than I can!

Also, both companies use major international suppliers like ABB, Siemens etc for transformers so, it's quite likely that regardless of voltage the actual units will look extremely similar, particularly in more modern installations.

ESB's been upgrading rural network in a pretty huge programme over the last few years. So, there are very few old xformers left. They're almost all newish ABB units, still can shaped though.

The telephone installations north and south of the border are DEFINITELY different. You can clearly see BT installations in NI and Eircom installations in the Republic. The wires are different looking, the poles look a bit different and the pole mounted equipment is totally different.

Also, the usual give away:
The telephone boxes are different

The best way you'll know you've crossed:

Northern Ireland : UK signs / road markings (all white lines):
Speeds/distances in miles
Triangular (euro style) warning signs.

Republic of Ireland:
Yellow line marks hard shoulder / edge of road
White line divides lanes
US/Canada/Aus style yellow chevron/diamond shape warning signs.
All speeds and distances in KM.
Direction signs marked bilingually.

I'll have to look at the poles/pylons though more closely next time i cross


[This message has been edited by djk (edited 01-08-2006).]

NIE use the same voltages as the UK RECs and so distribute at 11kV and 33kV, and their transmission lines are 132kV.

NIE have the same equipment as the UK RECs, use the same manufacturers etc and follow the same construction methods.

Ian

Ian,

Not quite

Voltages used in NI:

Transmission:

275kV (North-South Interconnector also operates at this voltage. Runs 30miles across the border and converts to 220kV at a station in the Republic) 2 X 2000Amp circuits.

110kV (same as the Republic) Rather than 132kV as in the rest of the UK.

There are also two single circuit interconnections at 110kV between Enniskillen – Coraclassey and Strabane – Letterkenny. These cannot be used for trade, but provide system security to electrically weak regions in both jurisdictions.

Distribution:
33kV
11kV

Source: SONI (Systems Operator For Northern Ireland)
A wholly owned subsidury of Virdian Group (this group includes NIE)
Under regulation from OFREG, S.O.N.I. Ltd also manages the commercial agreements with Generation companies and is the facilitator for the emerging energy marketplace in addition to the role of settlements system administrator.

NI is NOT part of the UK national grid system. It operates its own grid independently.

Interconnection:
North-South : SONI - Eirgrid
The main North –South interconnector is a twin circuit 275kV alternating current(AC) tower line, almost thirty miles in length. The connection points are at Tandragee on the NIE system and at Louth on the ESB system. As the ESB system operates at 220kV, intersystem transformers are required - these are situated at Louth.

The circuit ratings are 2000amp and the transformer ratings are 600MVA. There are two sets of first main protection both operating on the distance principle with acceleration – one set runs on BT private wires and the other link is provided by power line carrier equipment.

These circuits allow the two system operators to share spinning reserve requirements, thus saving costs and helping overall system stability. The circuits are also used to trade energy between the two systems by commercial operatives in both jurisdictions.

There are also two single circuit interconnections at 110kV between Enniskillen – Coraclassey and Strabane – Letterkenny. These cannot be used for trade, but provide system security to electrically weak regions in both jurisdictions.

Moyle Interconnector - to GB:

NIE – SP

The interconnection between NIE and SP is carried out using direct current(DC). There are two circuits connecting the two power systems and these are submarine cables approximately 55 km in length.

The cables operate at 250kV DC as two monopolar HVDC transmission systems rated at 250MW per pole, thus providing 500MW transfer capability. The HVDC converter stations are located at Ballycronan More (on Islandmagee in Northern Ireland) and at Auchencrosh (near Ballintrae in Scotland). These converter stations convert the electricity from AC to DC for transmission along the cable and then back to AC again. Power can flow in either direction.

There are two unique features to the equipment involved:-

i) The converter stations are the first in the world designed to use light triggered thyristors(LTT technology). With this technology the thyristors are not triggered by an electrical signal but by a pulse of light – this should make the process more reliable.
ii) The submarine cable design is also a world wide first in HVDC technology as the cables used have a coaxial construction i.e. a metallic ‘return’ conductor is provided as part of one cable.

The link is currently contracted to provide 125MW of power to NI as replacement for NI generation. The rest of the available link capacity (275MW) has been auctioned to energy traders in Ireland.


[This message has been edited by djk (edited 01-10-2006).]

That's a typical border crossing. As you can see rather uneventful

Yellow to white markings are about the only difference. And you can see where the two County Councils road maintenence starts and ends. A slight difference in choice of surface finish.

You can also see the last telephone pole in the Republic. That would just carry multicore cables running along the road feeding rural homes on its way.

During the 1970s, for security reasons, the British Army closed many many border crossings. These little rural roads were just "cratered" (had their surfaces severely damaged with heavy machinery/explosives) and had ugly baracades (usually concrete blocks and lots of barbed wire) dropped in.

This had the unfortunate effect of isolating already very isolated but interdependent communities on both sides of the border. What you have to realise is that pre 1921 there was no distinction between Northern/Southern (republic of) Ireland. So, communities and even individual farms often straddle the border. There are even a few towns e.g. Petigo in Donegal that litterally straddle the border.
Thankfully, in recent times, those roads have reopened and the communities, farms, villages etc are all reconnected again.
It was a shame, considering almost all of Northern Ireland's problems were concentrated in urban areas. For the most part, rural folk, who were deeply impacted upon by border arrangements, had nothing to do with any of it. I had elderly relatives who were cut off from their neighbours/relatives who had previously been a short 5 min drive away. Suddenly they had to drive 50+ miles or walk across fields under helicopter surveilence to visit them. So, calling over for a cup of tea became a bit more difficult. In many cases, they pretty much lost touch.

There's little/no cultural or social divide between those border areas. Don't forget that the traditional provence of Ulster isn't even all in Northern Ireland. Donegal, Monaghan and Cavan are in the Republic.

E.g. Donegal's natural urban hub is Derry/Londonderry. It was totally isolated from that for decades.

There would be less of a marked divide (in real, non political terms) than you would see at the English-Scottish or English-Welsh border.

Thankfully, things have moved on very drastically since those days and all of these places are reconnected again.


[This message has been edited by djk (edited 01-10-2006).]

I'm kind of satisfied to see that picture. I've never been to N.I., but got within a mile or two of the border once in Co. Cavan.


Here are two typical pole-mount xfmrs in England; maybe someone can confirm if these are typical of N.I. as well:



We are starting to see the more American-looking can-style transformers here as well though. This one is only a few miles from me:

That means that you have 1 phase distribution on the Isles?

I know 1 phase mains connections in very old installations here in Germany, and as a Standard in France for example, but distribution is usually 3 phase.

Wolfgang

We use 80A - 100A single phase services on "the isles"

3 phase isn't very common for residential, although it's increasingly common on farms.

Normally, most distribution networks would be 3 phase, but there might be a single phase 2-wire spur running several miles to a particular property.

@ Wolfgang

it's less costly to bring just two wires in rural areas with light loads. Since the wire size and insulator size is pretty much fixed, a third wire merely carries cost. (Transmission is different and so is distribution in densly populated areas)

On the other hand, it must be more expensive to supply 1 x 100A @ 230V than 2 x 50A 230/460V or 3 x 40A 230/400V if you already have a split phase or 3-ph LV network. Somehow, I get the feeling that thinking out of the box isn't encouraged in utilities.

Ireland in particular also doesn't follow European-style cluster development patterns. We tend to like the one off sprawling rural home. Hence we tend to have a lot of single phase spurs off the main 3 phase network.

Hello there again,
Intresting to see comments about single phase spurs being common in UK/Ireland. I have also seen O/H distrubition lines in Spain, and I noticed that hardly any of them where single phase, all I saw where 3-ph another thing I noticed is that many rural transformers seemed to be enclosed in hut type structures with the wires running down into them, I have also seen similar structures in France and Italy-is this common distribution practice on the continent? has anyone else noticed these or have any pics of these? and also noticed that most power poles in spain-even for LV lines
were of steel lattice construction rather than wood does anyone else know why this is? is it due to the Spanish climate? does any other country seem to use steel for distribution poles? Also does anyone know the distrbution/transmission voltages in use for Spain?-It would be intresting to know the voltages of those lines. Also can anyone else provide discribtions/pics of O/H distribution lines in various other countries-I find this pretty facinating-how about the Netherlands? Germany? Greece etc.

Perhaps some of you may be interested in these pictures of pole mounted transformers.

This is an old 5 Kva unit.



And here is a replacement 16 Kva unit.



Most people in Ireland will probably know which side of the border these pictures come from but does everyone else?

Martin.

Edited to correct link.

[This message has been edited by MartinX (edited 01-11-2006).]

Hello
Are these pics from NI and if yes is this equipment 11kV?
Luke

These pictures show an 11KV single phase primary with a 240V secondary (yes I do really mean 240).
And yes they are in NI.

Martin.

[This message has been edited by MartinX (edited 01-11-2006).]

ESB small xformers in the republic of ireland are *VERY* similar to the can-shaped device posted above.

10kV (being phased out) or 20kV.

Here's an old single phase service:





Eircom's rural telephone poles are re-used to carry multicore cables feeding homes en-route thesedays. However, they've really allowed the old wooden telegraph poles (>100 years old) to fall apart. They're simply not maintained as some only serve a few homes telco engineers simply never get to them.




[This message has been edited by djk (edited 01-11-2006).]

We're always interested in stuff like that around here! Welcome to the forum Martin.

Wolfgang,
Yes, to a limited degree. As soon as you get anywhere with a concentration of houses in a village or town you'll find 3-phase transformers with a 4-wire 240/415V distribution network around the settlement (each house tapped for 240V single-phase service).

In more rural areas though, you'll often see single-phase spur lines tapped from the 3-ph 11kV network running for relatively short distance to serve isolated houses. The two single-phase xfmrs in my post above are such examples, each one serving just a couple of houses which stand on their own in the countryside.

This being a mostly rural area, we also have little hamlets which have maybe a dozen or two homes spread out along a lane over a distance of maybe a half mile in what is otherwise a fairly isolated area. Some of these have a single-phase (2-wire) 11kV spur line and a single-phase xfmr which feeds 3-wire 240/480V distribution lines which run through the settlement, again with the houses just tapped for 240V 2-wire service.

Here's an example of the latter (notice the three LV wires and two fuses):


The single-phase HV spur in this example continues a short distance to a xfmr serving another tiny isolated community.


[This message has been edited by pauluk (edited 01-12-2006).]

The 16 kVA unit referred to above is made by a company called Pauwels Trafo in Cavan RoI.
I would expect that the ESB may use some of these.

Several people referred to the US style can transformer, I don't think I have seen a picture posted on this forum before so here is an actual example of a single phase or maybe I should say split-phase service for comparison.



Martin.

Link Edited.

[This message has been edited by MartinX (edited 01-12-2006).]

Now I'm amazed:

Is this a SWER system?

And are those 480V used in sort of an American way also?

Wolfgang

I hope I have not confused anyone but this is an actual installation in the USA. I think it is useful for comparison with what we have in the UK and Ireland.

Now I don't wish to drift away from this specific forum title ('Non-US')too much but briefly I will summarise what many of you probably know.

This US transformer primary is connected across phase and neutral/earth (ground) unlike in UK/Ireland where it would be connected phase to phase. This ground wire will run the whole way back to the source of the top phase wire, It is not SWER (Single Wire Earth Return).
The secondary is 120V - 0 - 120V with 3 wires being supplied to each house making 120V and 240V available in each house.
Any of our US friends could expand on this, I think I have got it fairly correct and there is probably a good link somewhere.

Paul posted a UK transformer above with a 240V - 0 - 240V output but every consumer is connected across 0 - 240V (2 wire) only, I think this is quite an unusual arrangement for the UK though.

Our Australian friends could tell us more about SWER and also 240V - 0 - 240V distribution in remote areas where 480V is used for some distant industrial/agricultural high current applications.

Martin.


[This message has been edited by MartinX (edited 01-12-2006).]

Just to address the title of this thread a little better here is a picture of a rural 110kV distribution line in NI that runs from substation to substation.
In damp conditions this line will 'sizzle' quite loudly and the corona discharge can be seen jumping the insulators!



And a close up.



Martin.

See the SWER topic by RODALCO just a couple of threads down this same category Non US systems and Trades.

Primary voltage here is 11 kV. Return path through earth at HT side.

Secondary at service transformers 230 / 460 Volts.
or 230 - 0 - 230 Volts.

I will post a few more SWER piccies next month while in the Coromandel, New Zealand.

Cheers Ray.

Most high tension lines here (110kV, 220kV etc) will "sizzle" during very damp conditions.

Irish drizzle can produce some unusually difficult conditions for electrical installations. You basically get a dense fine mist of rain that can cause all of the above effects.

Also, some of those 110kV lines in N.I. are probabally from the same era (they look simlar) to the very oldest parts of the national grid in the Republic. It's very unusual to see a corona, even on the oldest bits of the network though.

It's the same basic arrangement at the transformer, just with 240/480 instead of 120/240V. The difference is that in the U.S. the majority of homes get the full 3-wire service providing 120 and 240V whereas in Britain -- as Martin pointed out -- each house will just have its usual 2-wire connection for 240V.

There may be some farms or other larger installations which have the full 3-wire service and share the load though.

Yes, and in fact until quite recently I hadn't realized just how many of these were around my local area. After I spotted the first I kept a look out and realized that there are quite a few.

That's due the the rural nature of the area and the communities which have a number of homes spread out along a road.

As soon as you get into a place with a larger cluster of services, you'll find a full 3-phase 240/415V distribution system. You won't find either the basic 2-wire 1-ph or 3-wire 240/480V xfmrs in built-up areas.


They can be wired either phase-to-neutral or phase-to-phase in North America. They have a much greater variety of distribution voltages and arrangements than here, and in some cases a transformer with a specific primary voltage can be used phase-to-phase on one system or phase-to-neutral on another.

In the U.K., we never distribute a neutral conductor on HV lines, so a single-phase spur has to be run as two phases, as in the pictures above.

With the much greater distances in North America, presumably the savings on insulators and xfmr bushings by running as one phase plus neutral can be considerable.


[This message has been edited by pauluk (edited 01-13-2006).]

Sorry but I haven't got it completely.

As I see just four wires, does this mean HV and LV share the neutral (grounded) wire or is it just not visible?

In France for example even a LV neutral is regarded as an active conductor and is always isolated.

Here with us distribution is always 3 wire, usually IT (often with inductive starpoint to connection to earth).

The strangest thing about that topic is that I have never taken care of those poles as here where I live and work just everything is buried in the ground including phone, cable tv and the 20kV distribution. Only exception is 110/220kV feeding from the power station.

We are so to say more or less a pole free zone. Nevertheless there are quite a few places that have overhead connections elsewhere in Germany.

That American system would be a phase-neutral system, with the neutral shared with the LV system. Such is typical in urban areas.

I have never seen a Phase-Phase service transformer for single phase service.

.classicsat

Very common in rural New Zealand.
The primary HT side is taken of any 2 phases from the 3Ø line.
The secondary is either 230 - 0 - 230 Volts, so 460 Volts is available at the outer 2 terminals at 180° phaseshift , or both secondary windings are parallelled up to have 230 volts at double amperage.

for Wolfgang. at the primary there is one insulator visible in this case, photo from MartinX
and the return is via the earthed transformer tank. HT current return through earth only.
at the secondary 120 - 0 - 120 is available, in case of MEN the neutral is earthed. The secondary current loop is completed within the secondary windings from the transformer.

To feed a 1Ø SWER line an isolating transformer is required at the start of the SWER line e.g. 2Ø 11 kV to 1Ø 11 kV SWER and return path through a very good earth otherwise the feeder would trip on earthfault all the time.

Since I've never been "off contininent", I've only see NA setups, which I should clarify I haven't seen (at least residential) single phase phase-phase esystems here.

Yes, I realize that most of the world, at least the British colonies use 11KV delta.

Weren't some of the older distribution networks in North American cities ungrounded deltas? (e.g. 2400V).

Single-phase xfmrs would have to have been phase-to-phase on those.