Great Western Coffee Shop

How is this impacting their railways + transport, I'm wondering.

Mark

Long & medium distance trains have been halted, passengers rescued where necessary. Commuter trains restarted this evening in parts

From the BBC (https://www.bbc.co.uk/news/articles/cvgn7jgze2xo):

Managed to dodge any issues  flying home from Spain flying from Girona to Stansted this afternoon. The lights and everything else briefly went out across the airport but didn’t affect the running of the airport at all.

Arrived at Stansted bang on time so thought all would be well getting home until the wretched rail network we have said ‘hold my beer’ with multiple points failures at Reading and Westbury messing up the journey home so a big delay repay claim will be going in tomorrow.

When it comes to travelling to and from the airport in future it will never be by train ever again. Messed up big time last November and again today. It will be by car.

I shall await you posting here about a how a big smash on the M25 prevented you from catching your flight....

Oh dear, that post was so predictable Chris, I was expecting it  ::)

I have long held the view that ALL new electric trains should be equipped with either a diesel engine or a battery able to move the train at a much reduced performance for a reasonable distance.
In stating this, I was thinking primarily of UK conditions, but it looks as though it would be prudent overseas also.

At least affected passengers were allowed off the trains, in contrast to the UK policy of "keep them on the trains no matter what."

On a more general note, there appears to have been a regrettable lack of both battery emergency lighting and standby generation in public buildings.

The Times this morning had a quote from "energy bosses" that a "very strong oscillation in the electrical network" led to disconnection from "the European system" - i.e. France. I have not heard that anywhere else, so either the Times is very good at digging out sources, or it's wrong. Since it's what such bosses would have said if asked in advance what was the most likely cause of a hypothetical transmission grid collapse, perhaps it was basically a guess - by someone.

At a more recent press conference, the start of the collapse was said to be the disconnection of five (I think) nuclear generators, supplying more than half of of the demand at the time. Now, something must have caused that, and oscillation (instability) fits that bill. After that, total collapse was almost inevitable - it could only be avoided if the links from France (and Morocco, much smaller) could supply most of that deficit (15 GW), which sounds pretty unlikely.

Those links from outside all overloaded and tripped, though for the south-west of France the split was within France. They had to break the connection at the Pyrenees before resupplying from the French aside. The powering up of Iberia was done starting from the areas that could be supplied from abroad, in he north and south.

That sounds like the process I would expect to see. Starting the generators in a grid involves them following a grid already supplying power, so that was done using the external links. As much of the grid as could be supplied by those infeeds, at the north and south, was turned on and the generators in that area started up. That gives enough surplus power to prime the next areas and get them going.

Perhaps surprisingly, large grid systems are not well understood.
They are much too big and expensive to build a spare one for experiments. Only small and low risk tests and experiments can be performed on a working grid system.

Computer modelling is of limited use in view of the many variables, many of which change in unknown or unpredictable ways.

In recent years several factors have "conspired" to increase instability.
1) The increased use of switched mode power supplies. These draw roughly constant watts over a wide range of voltages, and can draw unexpectedly large currents during a supply voltage dip, this tends to increase the degree of voltage drop and may result in what would otherwise have been a brief voltage dip, now becoming a "fail to recover" event.
Note that variable speed motor drives and electronic lighting ballasts are all sub-species of switched mode power supplies.

2) Increased amounts of generation connected via static inverters rather than consisting of traditional rotating alternators.
Such sources CANNOT supply extra energy in a low voltage or low frequency emergency.

3)Increased geographical areas supplied by a common grid system. This tends to promote instability.

I expect more such outages.

These, and other, anecdotes suggest that wasn’t the case:

https://apnews.com/article/spain-portugal-power-outage-electicity-train-transport-8f22b5d7a760298773cd2659eb34a58a

There is some concern with Grid systems that rely heavily on renewable generation of the lack of inertia that spinning mass generation provides.  In the event of a fault on the transition system the Voltage takes longer to stabilise with  renewables based generation, Power Factor is also something more challenging the manage.

Black starting power stations ie a power station that has no live Grid takes time even natural gas fuelled.

It will be interesting to see the finding of the instigation[

quote author=broadgage link=topic=30210.msg361041#msg361041 date=1745947316]
I have long held the view that ALL new electric trains should be equipped with either a diesel engine or a battery able to move the train at a much reduced performance for a reasonable distance.
In stating this, I was thinking primarily of UK conditions, but it looks as though it would be prudent overseas also.

At least affected passengers were allowed off the trains, in contrast to the UK policy of "keep them on the trains no matter what."

On a more general note, there appears to have been a regrettable lack of both battery emergency lighting and standby generation in public buildings.
[/quote].

In the case of UK electrified railways the loss of traction power results in the loss of power to signalling, normally not a problem as there are independent locally sourced DNO supplies; however should an Iberian Peninsular type of failure occur there would be no DNO available.  And no putting generators everywhere of UPS's large enough to run for hours is not economically practical ................... quite simply the travelling public are not willing to cover the cost for what is an extremely rare event