EirGrid pushing to erect 400 new pylons

North Cork wrote: »

"No line of this size and type has ever been placed underground anywhere in the world.

That is an outright lie. I do sympathise with their case overall, on balance, but much less so when they lie so brazenly to make it

Mike 1972

Overground cheaper initially but higher maintenance costs due to weather related damage.

Underground in theory should be more reliable but takes longer to locate and repair faults when something does go wrong.

Would that be a reasonable summary ?

eirgrid refuse to bury anything, ever , no matter what. They are quite hysterical about it.

I suppose once they give in they are afraid it will become the norm. Underground HVDC is probably cheaper or only slightly more expensive at that distance than overground AC but eirgrid do not accept that HVDC is 'the same' as AC even though it is really ( at distance not for short runs ) except it uses a lot less copper overall and smaller pylons if overground.

Sooner or later we will need HVDC runs to the west coast if large scale wind harvesting is to become a reality. The demand in Ireland is not atypically 200km to 300km from the optimal areas for wind and HVDC makes sense at that distance.

If you want to expand the HVAC grid from Dublin to Drogheda ( say ) then it should be HVAC and overground, however this is not really what is being proposed here. I sense a monopoly at work

Carawaystick

there's only one interconnector capable of transferring decent amounts of power between the 6 counties and down here. this will be a second one and this extra redundancy will allow more power to be transferred across the energy market, as the original interconnector can be uprated as a fault on it won't have as severe consequences.

There is a synchronous grid so a dc interconector will not add any frequency control to the grid.

these anti pylon whingers are just luddites. they should feic off home and light their parafin lamps.

There's a transmission line from Turlough hill through the wicklow mountains, you'ld hardly see it except where people built houses under it at Holywood and the line running down the east coast is fairly unnoticable too.

That is an outright lie.

SpongeBob - where is the buried on-land 138km 400Kv line that you speak of?

I'm guessing this is the cross border line the article refers to;

http://www.eirgrid.com/transmission/meath-cavan/

More to the point, going by this, the North-South Interconnector is just the start of the pylon construction work.

http://www.eirgrid.com/media/Grid%2025.pdf

paulm17781

Sponge Bob wrote: »

That is an outright lie.

Where has it been done before?

HVDC ??

http://www.abb.com/industries/us/9AAC30300394.aspx

The switching station in Meath where this HVAC cable starts is where the HVDC east west HVDC link is supposed to come into Ireland and get upconverted to AC, it makes sense that a National HVDC feed terminates there too except that Eirgrid propose HVAC on Pylons instead.

As the purpose of Tyrone-Meath is mainly to deliver wind to Dublin ( and onwards) it should be a HVDC cable really.

Schematic of Woodland

http://www.eirgrideastwestinterconnector.ie/PE688-D199-005-001-003.pdf

The link from Woodland to the Coast ( 45km ) will be underground which is easy with HVDC.

Putting it simply, the ESB have probably chosen the wrong technology and are now blustering about the implemetation of the wrong technology.

http://www.eirgrideastwestinterconnector.ie/Ireland%20Land%20ER%20Non%20Technical%20Summary.pdf

Carawaystick

Sponge Bob wrote: »

Putting it simply, the ESB have probably chosen the wrong technology and are now blustering about the implemetation of the wrong technology.

http://www.eirgrideastwestinterconnector.ie/Ireland%20Land%20ER%20Non%20Technical%20Summary.pdf

ESB aren't doing this though, Eirgrid is. They run the grid both sides of the border.

On the other hand...
The esb have erected a string of pylons from Swords to Balbriggan but only strung up wires along half of it cos their planning permission ran out....
The unfinished section runs over the new MSA being built on the M1

Mike 1972

Would underground HVDC not create problems with magnetic compasses on the surface ?

They are shielded by soil at quite shallow depths. Anyway, what would you need a compass for in Cavan ???

Sponge Bob wrote: »

HVDC ??

http://www.abb.com/industries/us/9AAC30300394.aspx

The switching station in Meath where this HVAC cable starts is where the HVDC east west HVDC link is supposed to come into Ireland and get upconverted to AC, it makes sense that a National HVDC feed terminates there too except that Eirgrid propose HVAC on Pylons instead.

As the purpose of Tyrone-Meath is mainly to deliver wind to Dublin ( and onwards) it should be a HVDC cable really.

Schematic of Woodland

http://www.eirgrideastwestinterconnector.ie/PE688-D199-005-001-003.pdf

The link from Woodland to the Coast ( 45km ) will be underground which is easy with HVDC.

Putting it simply, the ESB have probably chosen the wrong technology and are now blustering about the implemetation of the wrong technology.

http://www.eirgrideastwestinterconnector.ie/Ireland%20Land%20ER%20Non%20Technical%20Summary.pdf

The link from Woodland to the coast is DC because it forms part of an interconnection between the mainland UK and the republic of ireland. This Interconnector Has to be DC as it connects two power systems that are not syncronised. They both operate at the same frequency (50 Hz), but the chances that both systems will be at the same frequency at the same TIME are remote. Hence you use DC as is effectively has zero frequency. You then convert to AC back when you connect into your power systems on either side of the interconnector.

Why do you convert to AC? Because thats the type of power your house runs on, thats what industry needs to power motors and machines and what not. Thats simple laws of physics. Nothing else.
The power system on the Island of Ireland, i.e. north and south, is run at the same frequency (50 Hz), so that the frequency down in dublin is that same as that in belfast all the time. This means that the connection between the two can be AC without having to go down the DC route.
If the two were connected at DC you would need huge converter station everywhere along the route that you needed AC power. The converter station are big, very big. I'm sure lots of those would be a blight on the landscape as well. That said, it wouldnt be as much a blight as digging an 80km long, 30m wide trench through the north east of ireland.

I would suggest before you launch into hysterics about this, that you get your facts straight. There are huge bodies of evidence available that support the overground argument from not just the parties involved but from other reputable sources worldwide.
Also as others have mentioned in the thread:

(1): ESB and EirGrid are not the same company.
(2): What you said about the below being a lie is in itself either a lie or a delusion. Show us some proof that its a lie?
"No line of this size and type has ever been placed underground anywhere in the world"

GenericUser wrote: »

The link from Woodland to the coast is DC because it forms part of an interconnection between the mainland UK and the republic of ireland. This Interconnector Has to be DC as it connects two power systems that are not syncronised.

Thanks for resolutely avoiding certain points I made, I mean that

That only explains why HVDC is always the best way to interconnect two separate grids.It does not explain why this link is entirely underground where eirgrid is adamant the link to the north must be overground.

Why do you convert to AC? Because thats the type of power your house runs on, thats what industry needs to power motors and machines and what not. Thats simple laws of physics. Nothing else.

Remarkable that

The power system on the Island of Ireland, i.e. north and south, is run at the same frequency (50 Hz), so that the frequency down in dublin is that same as that in belfast all the time. This means that the connection between the two can be AC without having to go down the DC route.

Of course it can, in fact there are no Non AC links on the island, I am making a case for considering them.

If the two were connected at DC you would need huge converter station everywhere along the route that you needed AC power. The converter station are big, very big. I'm sure lots of those would be a blight on the landscape as well.

You only need one in Tyrone and one in Woodlawne .....but WAIT !!!! There will be one in Woodlawn anyway

There are no intermediate demand points where you will convert to AC . Against that there are LARGE PYLONS ever 1/4km and the land take under the cables too.

That said, it wouldnt be as much a blight as digging an 80km long, 30m wide trench through the north east of ireland.

As against 400kv pylons, get real willya.

I would suggest before you launch into hysterics about this, that you get your facts straight. There are huge bodies of evidence available that support the overground argument from not just the parties involved but from other reputable sources worldwide. Show us some proof that its a lie?
"No line of this size and type has ever been placed underground anywhere in the world"

The real answer from the ex ESB types who run Eirgrid is is "We refuse to consider a technology we can bury, so BOO!"

paulm17781

Sponge Bob wrote: »

The real answer from the ex ESB types who run Eirgrid is is "We refuse to consider a technology we can bury, so BOO!"

So where has it been done?

paulm17781 wrote: »

So where has it been done?

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

There is a description of an upcoming 400km link to Shetland here

http://www.scottish-southern.co.uk/SSEInternet/uploadedFiles/Media_Centre/Project_News/Shetland/Documents_and_maps/Moray.pdf

Underground HVDC Cable
Two HVDC circuits will be laid in a trench at approximately 1m depth with the circuits
separated by approximately 5m. The cables will be laid following a standard
sequence of events involving: establishment of an approximately 20m wide working
corridor; excavation of sections of trench and bays in which the sections of cables will
be joined together; placement of cables in the trench and backfilling of the trench.
This will be followed by restoration of the working corridor. Detailed design of the
cable trench and its fill materials will depend on local ground conditions to ensure
appropriate heat conduction and cable protection. Maximum re-use of excavated
material is expected in most areas though there is the potential for a backfill material
(locally sourced) to be required immediately around the cable for its protection.
Lengths of cable of 700m to 1000m as well as any backfill material will be delivered
by heavy goods vehicle (HGV) using the public road network. The bays where the
lengths of cable will be joined together must be clean and dry and these will be
formed by building a concrete floor (or similar) in the base of the trenches of
Shetland HVDC Connection
Moray Underground HVDC Cable and Converter Station - Summary
approximately 10m by 5m, with a temporary cover to create the required conditions.
Once the joints are finished, the joint bays will be buried with no structure visible at
the ground surface.
Electromagnetic Fields (EMF)
Full compliance with legal standards (set by the Health Protection Agency) in respect
of EMF is achieved for all elements of the Shetland HVDC Connection and there are
no health risks. EMF within the converter station is controlled both by design of the
equipment and the building with any remaining EMF having dissipated to negligible
levels at the site boundary. The bipolar configuration of each HVDC cable circuit
involves one cable that is positively charged and the other negatively charged which
substantially reduces the effect of any magnetic field to below that of the earth’s
natural geomagnetic field levels. Any residual magnetic field is static (as opposed to
that of AC which alternates) and is similar to the earth’s natural geomagnetic field in
nature.
Maintenance
The converter station will be inspected regularly by SHETL and maintenance on each
circuit will take place on a planned basis at a frequency of between one and six
years. Periodic maintenance of the wider converter station site and any habitats
created during the construction and construction restoration phases will also be
undertaken.
The underground HVDC cables will be installed such that they do not require
maintenance except in the unlikely event of a technical problem requiring attention.
Experience suggests a rate of one failure every 130 years on the Moray section of
the cable. ( ie underground) If a fault occurs the required section of the cable will need to be
uncovered, repaired and the cable re-installed as originally.

Carawaystick

Is the grid in the shetlands synchronous with the rest of Britain?
The grid in all of Ireland is synchronous, i.e. 50Hz and the same phase.
Britain and Europe are all 50Hz, but out of phase with us and each other.
Can you show an underground link between different parts of the same grid to prove eirgrid are lying?

So the dc cables in your link are 1m down? a young boy could dig down to that, let alone some gob****e with a digger.

The max power demand in the 6 counties is about 1.5GW, down here it was about 5GW. The current connector takes a limited amount of power as it's constrained incase it fails and the two grids are islanded and fall out of phase.

Look up the historical prices of electricity before and after the single electricity market, prices dropped as soon as the market kicked in.
providing a second connector provides more reliability and allows more power be transferred from the cheapest generators.

Sponge Bob wrote: »

Thanks for resolutely avoiding certain points I made, I mean that That only explains why HVDC is always the best way to interconnect two separate grids.It does not explain why this link is entirely underground where eirgrid is adamant the link to the north must be overground.

Remarkable that

Of course it can, in fact there are no Non AC links on the island, I am making a case for considering them.

You only need one in Tyrone and one in Woodlawne .....but WAIT !!!! There will be one in Woodlawn anyway There are no intermediate demand points where you will convert to AC . Against that there are LARGE PYLONS ever 1/4km and the land take under the cables too.

As against 400kv pylons, get real willya.

The real answer from the ex ESB types who run Eirgrid is is "We refuse to consider a technology we can bury, so BOO!"

As opposed to the legions of armchair experts like yourself who refuse to believe that what the real experts (ESB, EirGrid...countless other system operators worldwide) are telling you is correct.

I didnt skirt around your DC point. The proposed line will be at 400kV. Lines at this voltage form the spine of the power system. If you want to have a strong power system, you need to have a strong spine. If there is a fault on a lower voltage section of the power system, you need this spine to absorb the fault and stabilise the rest of the system. As DC is not synchronous with the rest of the system, it provided NO Voltage support and hence will not be able to provide support in the event of a fault. So apart from the fact that the vast majority of the load on the power system is fed by AC current, this piece of infrastructure must be AC to provide a support to the rest of the system.

Even the local pressure groups have managed to grasp the difference between why AC and DC are different. And they are pressing for underground AC..and all the experts in this country and others have come out and said it isnt possible.

Sponge Bob wrote: »

Thanks for resolutely avoiding certain points I made, I mean that That only explains why HVDC is always the best way to interconnect two separate grids.It does not explain why this link is entirely underground where eirgrid is adamant the link to the north must be overground.

Remarkable that

Of course it can, in fact there are no Non AC links on the island, I am making a case for considering them.

You only need one in Tyrone and one in Woodlawne .....but WAIT !!!! There will be one in Woodlawn anyway There are no intermediate demand points where you will convert to AC . Against that there are LARGE PYLONS ever 1/4km and the land take under the cables too.

As against 400kv pylons, get real willya.

The real answer from the ex ESB types who run Eirgrid is is "We refuse to consider a technology we can bury, so BOO!"

And you still cant get your facts right.
Its Woodland not Woodlawn.

GenericUser wrote: »

As opposed to the legions of armchair experts like yourself who refuse to believe that what the real experts (ESB, EirGrid...countless other system operators worldwide) are telling you is correct.

I didnt skirt around your DC point. The proposed line will be at 400kV. Lines at this voltage form the spine of the power system. If you want to have a strong power system, you need to have a strong spine. If there is a fault on a lower voltage section of the power system, you need this spine to absorb the fault and stabilise the rest of the system. As DC is not synchronous with the rest of the system, it provided NO Voltage support and hence will not be able to provide support in the event of a fault. So apart from the fact that the vast majority of the load on the power system is fed by AC current, this piece of infrastructure must be AC to provide a support to the rest of the system.

Even the local pressure groups have managed to grasp the difference between why AC and DC are different. And they are pressing for underground AC..and all the experts in this country and others have come out and said it isnt possible.

Stabilise how?? What bit of the grid does this stabilise ???

How does it "support" the grid??

Where does it "stabilise" the grid ??

GenericUser wrote: »

And you still cant get your facts right.
Its Woodland not Woodlawn.

And it is to have HVDC switchgear no matter what it is called.

Sponge Bob wrote: »

Stabilise how?? What bit of the grid does this stabilise ???

How does it "support" the grid??

Where does it "stabilise" the grid ??

If you dont know the answer to those questions, you are in no position to be on here pontificating about methods for building electrical infrastructure.
I suggest you go and familiarise yourself with AC electrical theory, Voltage and Reactive support and then come back to the discussion when you are fully informed.
Perhaps you could apply for a job in one of ESB or EirGrid and show them how despite decades of experience and engineering best practise,they are completely clueless as to what they are doing. You could then explain to them in in-depth techical detail why you are right rather than posting on an internet message board. Put your money where your mouth is.

murphaph

GenericUser wrote: »

If you dont know the answer to those questions, you are in no position to be on here pontificating about methods for building electrical infrastructure.
I suggest you go and familiarise yourself with AC electrical theory, Voltage and Reactive support and then come back to the discussion when you are fully informed.
Perhaps you could apply for a job in one of ESB or EirGrid and show them how despite decades of experience and engineering best practise,they are completely clueless as to what they are doing. You could then explain to them in in-depth techical detail why you are right rather than posting on an internet message board. Put your money where your mouth is.

I support the 400kVAC over ground option here. Many Irish people don't seem to realise how common this sort of stuff is outside Ireland! However, from a purely technical point of view (being an electronic as opposed to an electrical engineer) I am curious about the above points. How does a 400kV "spine" absorb fault conditions from lesser parts of the network? (I'm guessing you're an electrical engineer)

GenericUser wrote: »

If you dont know the answer to those questions, you are in no position to be on here pontificating about methods for building electrical infrastructure.

Your brand of pontificating is bereft of any analysis and certainly not linked to anything supporting that which is evidently not there.

I suggest you go and familiarise yourself with AC electrical theory, Voltage and Reactive support and then come back to the discussion when you are fully informed.
Perhaps you could apply for a job in one of ESB or EirGrid and show them how despite decades of experience and engineering best practise,they are completely clueless as to what they are doing. You could then explain to them in in-depth techical detail why you are right rather than posting on an internet message board. Put your money where your mouth is.

I am more interested in why this particular line and why there. Explain this or simply butt out.

Sponge Bob, trust me, at this stage you are completely out of your depth. If I were you, I'd stop digging.

Murph, if you're really interested in this stuff, I suggest you try and blag a trip around the NCC in Ballsbridge. 10 minutes in front of the screen makes all of these issues very clear, particularly voltage support and network stability.

Try answering the simple question so Aidan1 , "why this particular line and why there" ...and do assume I know why the other 400kv lines were installed.

SpongeBob - I think at this point it's abundantly clear that you have no interest in anyone's perspective on this other than your own - thats the only implication I can take from the fact that you ignore the valid points put forward by other posters, and seem to be trying to suggest that there is some ulterior motive behind the construction of this line, either as it it, or at all (have we moved from HVDC vs AC?).

The reasons for the North-South interconnector, and it's priority over the rest of Grid 2025 are well known, and have been explained over and over in the public domain for years - there's no mystery there, and there's little to be added. Other posters have explained why this is being built at 400Kv AC, just like the other two lines already in place, and much of the rest of Grid 2025. You either fail to understand the rationale behind such infrastructure, and the relationship between AC transmission equipment and grid stability, or you have another solution.

Do tell.

Do explain or else link to the previous explanation you allude to Aidan1. No doubt the control room is groovy but I am not interested!

What's the question, why build it at all, or why build it as AC?

In any case, the answer is similar, to stabilise the grid over long distances. This doesn't just mean 'moving electricity', it means providing voltage and frequency support to a synchronised grid and Market. This, and the rest of Grid 2025 is also designed to leverage additional amounts of renewables onto the system by providing a more robust network.

Question for you. How much of the above can HVDC do?

Aidan1 wrote: »

In any case, the answer is similar, to stabilise the grid over long distances. This doesn't just mean 'moving electricity', it means providing voltage and frequency support to a synchronised grid and Market.

"why this particular line and why there"

This, and the rest of Grid 2025 is also designed to leverage additional amounts of renewables onto the system by providing a more robust network.

Yah, thanks for the eirgrid "boilerplate" aidan. Very helpful. Once I see the magic word "leverage" I know it is all good.

Question for you. How much of the above can HVDC do?

It can only deliver current at a point and these HVDC interconnect points to the AC network are expensive to build despite the relatively cheaper cabling portion. In general they are not considered at sub 500km land distances.....but what if the land portion were added to the east west portion.

Any comment on the rest of their plans Aidan ??

Sponge Bob wrote: »

Try answering the simple question so Aidan1 , "why this particular line and why there" ...and do assume I know why the other 400kv lines were installed.

Bob. I wont be 'butting out'. At this stage you seem to be having an argument with your own self. i'm am commenting on this debate because like other posters I actually know what i am talking about unlike the tripe that you keep spouting.
I would suggest if you are absolutley serious about carrying on in this discussion that you go and familiarise yourself with this topic. Otherwise take off the tin foil hat and find yourself something else to prattle on about.
The word 'Line' in your question above is particularily telling. It indicates you didnt even bother reading the background on the project. The Original post refers to a project that Eirgrid are building in the northeast. The are TWO sections to this project. One is an "Interconnector" between the north (tyrone) and republic of ireland (cavan). Technically speaking as the two systems in ROI and NI are run at the same frequency it shouldnt be referred to as an interconnector. Really it is only an interconnector in the sense that it crosses a political boundary. Effectively it is a power line to enable power to be transferred within the island, the same as any other power lines. The current North south line has no where near the capacity needed to economically do this and hence the capacity needs to be increased.
Both power systems operate at 50 Hz AC and hence the power line needs to be built as AC.
The second section of the project is another standard power line to reinforce the ageing infrastructure in the north east (meath, cavan etc). This is the line that will run from woodland to cavan. This will mean power can flow from dublin to woodland to cavan to tyrone or from tyrone to cavan to woodland to dublin or a combination of the two or to and fro west of woodland. This cant be done with a dc link. So there ya go bob. Had you bothered your arse to read about the project, you would have seen it wasnt just about transferring power from ROI to NI or vice versa, it was about reinforcing and improving the power system in the north east of the country. But then again, your thinking seems quite one dimensional, so I'm not too suprised really.

I have highlighted two words above in italics. Ageing infrastructure. Its old, it got to creaking point with the boom years, its now coming to the end of its useful life and needs to be replaced. This is true for the whole country. What is being done through projects like the above is the replacement of this vital infrastructure with something that can not just handle todays needs, but can also handle the power needs of a growing country for many years into the future. The entire country (and the world) runs on AC power. Hence the infrastructure needs to be AC. Its as simple as that.

Another thing Bob. I and other posters have answered all your questions. You still havent told me why you havent applied for a job in ESB or EirGrid. As it happens, I see one of the two above is starting to post jobs on its website. Why dont you apply for one of the jobs? You cleary are the foremost expert on electrical infrastructure in this country, it is simply astounding that you dont work for one of these companies.