Another power question (as shown by GridWatch)

The Belgians would nick it on the way, or more seriously would who ever runs their grid charge more for transferring it than we do.

Bit on the Local radio here this morning about the possible connection from France to the UK terminating in the Gosport area which has been bubbling away quietly for a year or so.

This would then be connected in to existing grid infrastructure which is now partly underused since Fawley Power Station closed.

G.Harman

Yes, when the current France->UK link near Dover broke over the winter, some of the news sites picked up the map for the new proposed one and showed that by mistake.

The UK will not be losing out in any transfer.

The DC interconnectors operate on a system operator to system operator basis and a traded defined capacity auction basis where the capacity released for trading is effectively being determined by the system operators.

There are limits on what particular cable and overhead circuits can handle. If the transfer capability across the Dutch-French border is thermally or stability limited then a transfer via the UK would not be out of the question. There are use of system charges that will need to be paid but if the energy is needed and there are no other options then that is the route it will flow.

All transfer quantities across the DC links are by design and action deliberate. Changes in generation or demand on the AC system here, or in France, Ireland or the Netherlands is not reflected in changes in interconnector transfer levels.

Didn't know that ran that hot...

Especially as the only French-Dutch Border is on on the Caribbean Island of Saint Martin. Those would be long links.

G.Harman

Well call it Belgium then FFS.

Cables don't but modern overheads are regularly operated considerably above the boiling point of water.

Therre' need to be an interconnect by passing Belgium for that to happen,

In article , The Other Mike scribeth thus

How hot JOOI?...

Whilst I don't know the answer, I remember being told on a CEGB course that transmission wires have significantly more capacity in cold weather than hot: one of their limits is the amount of "sag" caused by thermal expansion.

I was also curious. A bit of Googling suggests different temperature specifications for different power-line materials, but I didn't find any specific temperatures, only upper limits specified. In the UK I had the impression it was in the 50 - 90 °C range, but elsewhere, possibly in the US, temperatures considerably higher were mentioned, over 200°C. Problems with cables that get hot are that they sag more as the metal expands, and that aluminium cables lose strength above their annealing point. There's stuff here

I heard in a lecture about their approach to the need for greater capacity in a particular overhead line receiving wind farm output. They were able to make better use of the line capacity by monitoring and modeling actual conductor temperature.

It was of significant help that wind farm output was greatest when the wind was perpendicular to the line and thus gave greatest cooling.

Chris

I can believe that they run warm but how can birds sit on them for so long if they are at that sort of temperature?

Birds seem to like the cables round here on frosty mornings which tends to suggest they are warm. Only snag is when a flock of seagulls crash into the horizontal 11kV lines and end up hanging there still alive.

why would they not be alive?

En el artículo , newshound escribió:

Some of them so seem to sag close to the ground; I often wonder why they don't arc over, especially in rain.

Many years ago on a walk in the country, we passed through a spinney under the centre of some Grid lines. You could hear quite significant corona discharge(?). We hurried away.

How pathetic. I've lived in places like that

In the village where we lived previously there were power lines (132kV IIRC) crossing a local lane. You could clearly hear them fizzing, especially on quiet misty evenings when everything was damp.

They typically hit the thin lines at full flight speed and break wings crashing to the ground where buzzards, foxes and the like see them off. It must be a weakness in seagull flocking behaviour or vision - they don't seem to see the thin HT wires at all.

The ones left hanging by a wing on the wires suffer for a long time.