The ESB And Eirgrid can go f*ck themselves - Merge

Freddie59

Zen65 wrote: »

after all the networks in cities usually are underground.

Actually, no. The 220V network is underground in most modern (last 30 years) estates. But all 10Kv and beyond plant is overhead.

Bruthal

Freddie59 wrote: »

Actually, no. The 220V network is underground in most modern (last 30 years) estates. But all 10Kv and beyond plant is overhead.

You will be doing well in city centre`s to see many 10kv+ overhead lines. And im sure that the actual city centre`s and close by were what was meant, rather than the estates in the suburbs.

pljudge321

Zen65 wrote: »

Now with my physics & engineering hat on: I would imagine that at high voltages it would be a problem to put bits of the network underground. Leave aside the obvious reason (everybody would say their bit was to go underground) but since cable has high capacitance and overhead wires have relatively high inductance, putting bits of cable & wire in series would lead to a circuit with a lot of circulating current & "ringing". I don't know how close to their voltage margins the cables are operating, but failure of the cables would surely be far more frequent if such circuits were constructed? I'm sure there are other technical reasons for not building circuits like that. Maybe somebody here who is more closely involved in such matters could educate me?

Z

For your reading pleasure: Eirgrid Tepco Report

Zen65

pljudge321 wrote: »

For your reading pleasure: Eirgrid Tepco Report

Many thanks, I must dig out some of my old engineering notes to read this in full.

Z

ytpe2r5bxkn0c1

loremolis wrote: »

can the line be dropped off an overhead system into an underground system and back up to an overhead system as simply as that?.

No. As I pointed out earlier. They are completely different types of wires. The overhead is about €19 per Mt while the UG cables are at least €215 per mt.

ytpe2r5bxkn0c1

Paparazzo wrote: »

Yes it can be done. It's common across motorways, and when a group of houses are built under a line it's common for the line to be converted to underground for a single span.

Only for short distance. It is different cable. You cannot just drop the overhead conductor into a duct underground.

Zen65

Freddie59 wrote: »

Actually, no. The 220V network is underground in most modern (last 30 years) estates. But all 10Kv and beyond plant is overhead.

Clearly you're not correct in saying this. If you ever have had to contact ESB Networks for information about their networks (Dial-Before-You-Dig) you'd see that the city is littered with 10kV and 38kV underground networks. There's also a lot of 110kV underground networks in Dublin (including a cable which runs very near to my house). The generation plants in Poolbeg / Ringsend are all connected at 220kV so that's all underground in Dublin too.

Of course there will be plenty of 10kV overhead networks in the suburban parts of any city, but mostly only in the less-populated areas. There were 38kV lines near my house 10 years ago but they were put underground through a park.

In reading the initial part of the TEPCO report posted here by pljudge321 it does indeed seem that there are voltage issues arising when parts of a high voltage circuit are put underground. There will be solutions to each of these problems, but they cost even more money (more insulation, additional surge arrestors, and something ominous called "operational countermeasures").


Z

PS: Does anyone have an update to what's happening to Teresa?

loremolis

Alexa Billions Pension wrote: »

No. As I pointed out earlier. They are completely different types of wires. The overhead is about €19 per Mt while the UG cables are at least €215 per mt.

If there is no way of joining a HV OH cable to a HV UG cable?

If not, then what Ms. Treacy is looking for cannot be done as the line on both sides of her land is overhead.

loremolis

Zen65 wrote: »

Clearly you're not correct in saying this. If you ever have had to contact ESB Networks for information about their networks (Dial-Before-You-Dig) you'd see that the city is littered with 10kV and 38kV underground networks. There's also a lot of 110kV underground networks in Dublin (including a cable which runs very near to my house). The generation plants in Poolbeg / Ringsend are all connected at 220kV so that's all underground in Dublin too.

Of course there will be plenty of 10kV overhead networks in the suburban parts of any city, but mostly only in the less-populated areas. There were 38kV lines near my house 10 years ago but they were put underground through a park.

In reading the initial part of the TEPCO report posted here by pljudge321 it does indeed seem that there are voltage issues arising when parts of a high voltage circuit are put underground. There will be solutions to each of these problems, but they cost even more money (more insulation, additional surge arrestors, and something ominous called "operational countermeasures").


Z

PS: Does anyone have an update to what's happening to Teresa?

I tried to read that report but my head melted.

As for Teresa, I think that story will disappear now that she's out of prison.

http://www.thejournal.ie/teresa-treacy-meets-young-supporters-after-release-from-jail-249565-Oct2011/

pljudge321

loremolis wrote: »

If there is no way of joining a HV OH cable to a HV UG cable?

If not, then what Ms. Treacy is looking for cannot be done as the line on both sides of her land is overhead.

It can be done, it would require steel termination pylons at either side of her land and a rather large trench being dug with the trees being removed and nothing being allowed to be planted above the trench run.

It won't happen anyway.

You can see a couple of the underground to overhead pylons if you are driving on the M50.

http://upload.wikimedia.org/wikipedia/en/1/17/Termination_Tower.JPG

Bruthal

pljudge321 wrote: »

It can be done, it would require steel termination pylons at either side of her land and a rather large trench being dug with the trees being removed and nothing being allowed to be planted above the trench run.

It won't happen anyway.

You can see a couple of the underground to overhead pylons if you are driving on the M50.

http://upload.wikimedia.org/wikipedia/en/1/17/Termination_Tower.JPG

I wouldnt say thats 110kv in that photo though.

pljudge321

robbie7730 wrote: »

I wouldnt say thats 110kv in that photo though.

That's the only pic I could find, the 2 conductors per phase on that pylon would indicate its probably in the region of 200 kV.

Bruthal

pljudge321 wrote: »

That's the only pic I could find, the 2 conductors per phase on that pylon would indicate its probably in the region of 200 kV.

Around the 38kv at most i would of thought. And probably less.

Probably 2 circuits, rather than 2 conductors per phase. Cable ends far too close together, insulators much smaller than 110kv would be.

loremolis

pljudge321 wrote: »

It can be done, it would require steel termination pylons at either side of her land and a rather large trench being dug with the trees being removed and nothing being allowed to be planted above the trench run.

It won't happen anyway.

You can see a couple of the underground to overhead pylons if you are driving on the M50.

http://upload.wikimedia.org/wikipedia/en/1/17/Termination_Tower.JPG

Thanks.

I've seen pylons dropping cables from overhead to underground along the M50 but they look like 38kv. I haven't noticed any 110kv.

If it is technically possible, why do you think it "won't happen anyway"?

Paparazzo

Davy wrote: »

Its not common for 110kv. Its easy to do for 10kv or not to bad for 38kv but 110kv is a whole lot bigger. A pylon would have to be built on both ends for it, and then put the cables up it, and make them off into special connections. I wouldn't say its cheap either

Yes, its almost never done for 110 or 220. Happens a lot for the lower voltages.

pljudge321

loremolis wrote: »

Thanks.

I've seen pylons dropping cables from overhead to underground along the M50 but they look like 38kv. I haven't noticed any 110kv.

If it is technically possible, why do you think it "won't happen anyway"?

They won't want to set a potentially incredibly expensive precedent. The grid is about undergo a massive upgrade in order to facilitate the couple of gigawatts of wind planned for 2020. We won't be able to afford it if there is a precedent for forcing a line to go underground. And that's ignoring the operations problems such a scenario would entail.

ytpe2r5bxkn0c1

loremolis wrote: »

If there is no way of joining a HV OH cable to a HV UG cable?

If not, then what Ms. Treacy is looking for cannot be done as the line on both sides of her land is overhead.

Not was was said. You asked could the overhead be dropped underground and it can't. Ug can of course be joined to OH but it's the cost of the UG section that is the issue.

loremolis

Alexa Billions Pension wrote: »

Not was was said. You asked could the overhead be dropped underground and it can't. Ug can of course be joined to OH but it's the cost of the UG section that is the issue.

My mistake.

Paparazzo

Considering they're already altering a route that was picked because it was far away from houses, they're doing enough by moving it. Fair play to the neighbours, they're volunteered to having a HV line close to their houses to save a few of yer ones trees.

joela

Paparazzo wrote: »

Considering they're already altering a route that was picked because it was far away from houses, they're doing enough by moving it. Fair play to the neighbours, they're volunteered to having a HV line close to their houses to save a few of yer ones trees.

Really, where did you hear that? She still has her Teresa Treacy support group on site, apparently they are receiving donations and food from all over Ireland:rolleyes:

ytpe2r5bxkn0c1

The original route was already altered to minimise the impact on her trees although it brought the line closer to homes.

joela

Alexa Billions Pension wrote: »

The original route was already altered to minimise the impact on her trees although it brought the line closer to homes.

I heard it had been realigned slightly but not that it had brought it closer to other peoples homes!

Paparazzo

joela wrote: »

I heard it had been realigned slightly but not that it had brought it closer to other peoples homes!

Well, guess work on my part. The original route was chosen because it was a minimum impact on homes. I don't know the new route, but it was changed and eirgrid thanked neighbours for their co-operation. Would be interesting to see the old route and the new route on google maps.

loremolis

Freddie59 wrote: »

http://ec.europa.eu/energy/electricity/publications/doc/comp_cost_380kV_en.pdf

http://jcots.state.va.us/pdf/CostAnalysis.pdf

It's not 8 times - it's up to 25 times more expensive.

It's kinda hard to argue that these figures are not "automatically correct" as you put it. Which seems to be why you are continuously avoiding commenting on them.:)

This document is available on the CER website under the "Standard Transmission Charges and Timelines" section.

http://www.cer.ie/GetAttachment.aspx?id=f86e6651-dfe1-4bef-aea7-e3d3ca585e0c

It presents the actual cost per km for the supply and installation of a 12km underground 110kv cable (described as 630mm2 Al) by ESB Networks to serve a windfarm at €6,033,063.

At an invoiced cost of €502,775 per km for underground 110kv (albeit on roadway), if the undergound line is actually 25 times more expensive than the OH line, then the OH line would come in at €20,111 (clearly way too low).

8 times more expensive gives a figure of €62,846 (still seems too low).

The CER decision document on this contains costings per km for several different types of HV OH and UG lines.

http://www.cer.ie/GetAttachment.aspx?id=0e95c64f-80f9-4487-b9c9-88f56b8209a5

Appendices A & C refer.

Can anyone understand the different cable sizes listed in those Appendices in order to, once and for all, provide an accurate ratio of how much more expensive UG is?

I would try myself but I'm not sure if I'm comparing like for like.

While I don't think that the ESB will underground Ms. Treacy's line because of the precedent it would set, I'm still curious as to the actual cost difference.

Dudess

I can only imagine how gutted some protest fetishists are about her being released...

joela

Poor neighbours, how come they were so ok with it? I thought the Teresa Treacy Support group were holding a public meeting last Friday night for all the locals who were against the powerline. I wonder how that went?

It seems absolutely nuts that they are bending over backwards like this, wish they would just get a court order for the lot of them! Send them all to jail and lash into the trees, job done! End of non issue and silly support groups.

joela

Dudess wrote: »

I can only imagine how gutted some protest fetishists are about her being released...

Ah sure no, they have a website and support group and donations from all over Ireland. They seem to be setting up another Shell to Sea job but for a cantankerous old biddy and her tree plantations.

DublinRescuer

This is F****NG stupid... i hate the law for this reason.. the poor lady was only trying to protect her earth and she gets sent down for it... this begs me to wonder why i dont end my fecking life if we are resulting to attacking ppor ladies, stupid world

loremolis

DublinRescuer wrote: »

This is F****NG stupid... i hate the law for this reason.. the poor lady was only trying to protect her earth and she gets sent down for it... this begs me to wonder why i dont end my fecking life if we are resulting to attacking ppor ladies, stupid world

No need to do that.

The lady seems well able to look after herself.

Stark

No need to go to such extremes. You just need to cut yourself off from the electricity grid and live by candlelight. Then you don't have to feel guilty about electricity lines going through anyone's land.