Did you know ? Questions answers ecology and energy.

[Other]

Hello,
Certain they know how to measure losses in a line
The longest line that descends from Churcill falls Au Labradore
is more than 1000km and it is measured at the exit of the dam and re-measured at the main station, (not to mention that along the way there are breeders)
Between the billing and the barrier there is a whole world,
Line losses at 750 volts, losses in breeders, losses in transformers 000 volts then redistribution and new transtormed into 230 volts
distributed everywhere with lots of individual transformers
110/220 for homes, or 550 volts for growers and small businesses, not to mention that the 13 line passes close to tree branches, when it sells it crackles everywhere.

Some line losses are sometimes useful in the event of a heavy fall of ice overloaded lines are less vulnerable, and sometimes it voluntarily overloads the line in case of ice, because if a cut occurs it becomes difficult to get rid of the ice on the wires and the insulators, He sends 2 or 3 shots of current running it everywhere and the ice is gone ...

For your network in France it is a lot of small power stations to connect to a loop so even more difficult to determine with precision the loss in the line.
Although they know what each power plant produces and know what is consumed, but there is more talk of line losses but total losses, But I'm not worried for them it passes the bill on to consumers and more particularly to the little one.
A small steel mill that produces 600 tonnes of steel annually pays more than $ 000 million of electricity per month, the same amount for electrode carbons and $ 1 monthly for natural gas.

Andre

[zac]

Ben they must have an idea all the same ... since they know what they produce and they know what they charge .... the differential = the losses (not necessarily that online there is the transformer also ) ...

Hello
and the "unknown markdown", how does mowing in French count it?
@+

[Christophe]

Hello
and the "unknown markdown", how does mowing in French count it?

Don't worry about that, they must have good tools!

[Bougonnator]

Hello,

Five years ago, EDF Production Transport estimated the losses on the network at the power supplied by a 1300MW reactor.
This is why EDF carries 400kV: by increasing the voltage, the current is reduced and the ohmic losses on the network too. Increasing the voltage further poses problems with the dimensions of the infrastructure for dielectric insulation.
It is also for this that the lines are not buried: there should be a wide trench of more than 30m on which we could do nothing or plant nothing.
Little anecdote not verified: after the war, while the country was under reconstruction, EDF then newly created, would have received a government directive ordering him to build the lines on the reliefs to show the people that the country was under reconstruction. Today, we no longer find this very beautiful.
A solution ? Local production, at the place of consumption.

[Christophe]

1300 MW whereas there are 57 reactors in France (not all of 1300 MW) that makes roughly at least 1/50 = 2% of losses (when all the reactors work in full) ... In "reality" ca must therefore be 5 to 10% since the average load is obviously not 100% all the time (and fortunately).

It is a lower figure than the one I thought (10 to 20%) but if these are the "official" figures we will believe them huh

[Other]

Hello
In the pertent on a line there is not only the resitance of the conductors, it is also necessary to take into account the frequency,
the higher the frequency, the more problematic this is.
The choice of a standard frequency for its reasons Europe chose 50 HZ and America chose 60 HZ (not to make like the English be different in all these norms to satify the exclusive market of Commewelt, but for reasons economic

At first the frequency was 25 hZ

With 60 Hz is 20% higher than 50 Hz
it takes 20% less wire on the windings of the transformers and motor, it allowed the motor to run at 3600 rpm against 3000 rpm 50HZ, although currently with the generalization of DRIVE it does not matter anymore.
This makes smaller motors for the same power.
Certain welding machine raises the frequency to 900HZ just to have a small transformer with a ridiculous winding. some turns (besides this principle is used in all power suppli of computers)

Ideally we should increase the frequency, but for transport this poses problems. Some line are DC
The highest are in 750kv that makes tower monuments especially where it crosses the ST Laurent river.

In AC current we speak KVA and the frequency enters into the calculation
In DC current we speak KW

Andre

[MichelM]

Hi free electrons
Well I looked a little at work the losses are not as large as you think (do not exaggerate it is not a gasoline engine!) In 2005 the losses in line and in transformation at the level of transport network ( RTE electrical transmission network from 400 KV to 63 KV) are 2,3% or 12 GWh for 023 GWh produced, 522 GWh exported. In relative it is not too much, in absolute it is still 694 nuclear unit (60 MW) permanently. There are still losses on the distribution side but there in my opinion the biggest losses are rather the wild connections.
For 50 Hz I think it's largely historic, the majority of networks were already in 50 Hz, there was a bit of everything before EDF. In Paris for example there was a direct current distribution (elevator of department stores?), Single phase and three phase of course but also not so long ago two phase ... etc.
For the size of the transformers even in 50Hz it has decreased a lot. I participated in the commissioning, for example, of 600MVA autotransformers which were almost the same size as the 300MVA (20 years difference).
For the connections by cables in 225KV one hardly exceeds 15 Km, idem 400KV (surely less) there are too many losses (condenser effect of the cable). By cons for short links I do not see why there should be a very large trench? In a post you can put your hands on it, they have the same external size as 20KV, it is obviously the insulation which is much thicker and the metal core smaller. For heating there is less at equal power ...
For long submarine cable connections (France England; Sardinia Corsica) direct current is therefore used. There are too many losses in alternative from 45 km compared to continuous, despite the conversion stations.
Ex: IFA (France England) 2 MW, 000 km including 70 km underwater, 45 dipoles of 2 MW, DC voltage between poles 1 KV.
There would still be a lot to write but the main thing is to know that there are not that many losses in electrical systems, even the motors have very good yields (more than 90%).
Small remark for the nuclear power stations it seemed to me that some had heating circuits for greenhouses. I saw some (cogeneration) with a conventional thermal power station (coal) but it was out of service? Political reasons? Pity.
Michel

[pluesy]

Hello...

From the head, a 5 MW wind turbine has approximately (the specialists please correct me) a rotor of 60 m in diameter and a height of 120 m in the nacelle. These models are 100% offshore ...

A "good" conventional terrestrial wind turbine makes 1 MW ... so you have to apply a coef. 5

I do not know for the offshore (the winds are stronger so the blades must be smaller ...) but for the terrestrial I put a pdf on your site which describes the biggest from nordex (90m in diameter and 2500 kw at 14m / s) the main technical info are page 6 and 7 of this pdfof 20 pages

for docs fans they have a pdf for each of their models and herea short description of the offshore version of their biggest model

[Christophe]

Figures of the day : The kilo of veal is equivalent to a car journey of 220 kilometers! The suckling lamb: 180 kilometers! Beef: 70 kilometers! Pork: 30 kilometers! (without counting the carbon contributions from packaging, consumer travel and cooking). This is the part of the carnivorous diet in terrestrial fever! For comparison, the production of 1 kilo of wheat or potatoes is barely equivalent to a car slot.

Gesture of the day : I turn off the equipment. Turning off the standby of a computer and its printer saves 100 to 200 kWh per year.

Source: mailing list Nicolat Hulot

Conclusion: eat pork bread and potatoes!

Otherwise The Nicolas Hulot foundation which "promotes" travel is not really consistent
http://www.defipourlaterre.org/agir/ale ... r/voyages/

[denis]

Did you explain these figures better?
what is it, carbon cost equivalence, production blow ??

In this genre: Oil is not expensive, because it costs 1000 times less expensive than human energy !!! : imagine paying strong men to push a car at 30 km / h