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#144679 - 01/08/06 10:03 AM Republic of Ireland/N Ireland distribution/transmission lines questions
lukemcuk Offline
Junior Member

Registered: 01/07/06
Posts: 6
Loc: UK
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

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#144680 - 01/08/06 10:27 AM Re: Republic of Ireland/N Ireland distribution/transmission lines questions
RODALCO Offline
Member

Registered: 12/08/05
Posts: 863
Loc: Titirangi, Akld, New Zealand
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
_________________________
The product of rotation, excitation and flux produces electricty.

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#144681 - 01/08/06 03:39 PM Re: Republic of Ireland/N Ireland distribution/transmission lines questions
djk Offline
Member

Registered: 12/26/02
Posts: 1269
Loc: Ireland
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).]

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#144682 - 01/10/06 01:03 AM Re: Republic of Ireland/N Ireland distribution/transmission lines questions
ianh Offline
Member

Registered: 06/16/04
Posts: 52
Loc: Douglas, Isle of Man, UK
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

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#144683 - 01/10/06 01:52 AM Re: Republic of Ireland/N Ireland distribution/transmission lines questions
djk Offline
Member

Registered: 12/26/02
Posts: 1269
Loc: Ireland
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).]

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#144684 - 01/10/06 02:21 AM Re: Republic of Ireland/N Ireland distribution/transmission lines questions
djk Offline
Member

Registered: 12/26/02
Posts: 1269
Loc: Ireland


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).]

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#144685 - 01/10/06 07:34 AM Re: Republic of Ireland/N Ireland distribution/transmission lines questions
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
 Quote:
That's a typical border crossing.


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.

 Quote:
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.


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:

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#144686 - 01/10/06 02:34 PM Re: Republic of Ireland/N Ireland distribution/transmission lines questions
Wolfgang Offline
Member

Registered: 09/25/05
Posts: 154
Loc: the very West of Germany
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

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#144687 - 01/10/06 02:40 PM Re: Republic of Ireland/N Ireland distribution/transmission lines questions
djk Offline
Member

Registered: 12/26/02
Posts: 1269
Loc: Ireland
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.

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#144688 - 01/11/06 01:03 AM Re: Republic of Ireland/N Ireland distribution/transmission lines questions
C-H Offline

Member

Registered: 09/17/02
Posts: 1508
Loc: Stockholm, Sweden
@ 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.

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