Journeycheck's signal to noise ratio isn't good. It feels as though that approach risks boosting the noise.

Mark

 

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

 
Journey check has recently been adding explanations of technical issue and, whilst the more experienced of us may give a wry smile and say "surely we all know that" ... actually some of guest readers may not.  I suspect these explanations are prepackages chunks of text - I may be starting a collection here

 
From https://www.wiltshire.gov.uk/localtransportplan

 

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

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

 
It is forecast to be into the mid 20s today in Ústí nad Labem.

 

Too much information. 

 
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.

 
I put the shorts on for the first time this year.

And Finn had his cooling mat for the car.

 
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.

 
An on-the-ground account on this Substack blog. The conflict really is dismal.

Mark


https://martinrobbins.substack.com/p/i-visit-britains-most-expensive-farm

 
Back in the 90s I set out to walk the K & A in a series of stretches, usually around 12 miles. Living in Maiden Newton I set out using the train. The stages I embarked on were Bath to Bradford; Trowbridge to Avoncliff ( for the Cross Guns); Trowbridge to Devizes for bus to Bath; Pewsey to Devizes for bus to Bath; Pewsey to Great Bedwyn; Bedwyn to Hungerford; Hungerford to Kintbury. I never got round to the last section.
The walks were helped by there being an hostelry every four miles or so.
In addition these guides were very useful.

 
From the BBC:

 
In years gone by, there was a regular shipping service between Minehead and South Wales, this conveyed coal to the Minehead gas works, and bagged coal for household use.
Gas production ceased decades ago, but the gas holders remained until recent years. Almost no trace remains today, but the location is still known as "gas works beach" by anglers. It was on the edge of town, past the lifeboat station.

Seagoing sailing barges were used, and later small steamers. Passengers and livestock were carried in return for a suitable gratuity. The vessels used were not licensed to carry passengers.

 
From the BBC:

 
There were - but apparently they weren't wide or intimidating enough! 

 

Still ongoing, now forecast disruption until 2000

 
Chippenham? I thought there were barriers there already?

 

I presume that no one foresaw any need to prohibit the practice. Back in the days when a driving test was available promptly on payment of the fee, nothing was gained by bulk buying and then reselling test slots.
These days there is a clear financial incentive.

 
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.

 

Here's the proof, and comparison to other services:



Because of the very thin service, any cancellation is serious.

 

This train has run 89 times in the last six months, in which there have been 130 weekdays.  28 of those days it was cancelled because of planned engineering, 2 because it was Christmas / Boxing Day.   So 100 "should" have run. 11% cancellation rate - a very high percentage for a weekday.

 
Like the old platform 1 at Westbury, it would look much better with a railway line next to it.

 
On what was just a plain old platform we now have this lot ...

 

It's in "Oh no - not AGAIN" territory ...  known as being a risky train. I will look at putting some numbers on it some time.

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

 

Cancelled as the guard for those services is booked to arrive at Westbury on the 1C77 10:35 Paddington to Exeter St Davids service which is currently being diverted via Swindon. Not the first time that problems or delays with 1C77 see the Swindon services cancelled.

For the record, the points failure at Westbury yesterday caused the cancellation of the 2M28 15:15 Swindon to Westbury and 2M21 16:23 Westbury to Swindon services. The unit stayed in the bay platform at Swindon and became the 17:35 departure to Westbury.

 

To really answer that you would need to know how often that service runs on a Sunday's via the B&H

 
Only 2 trains in GWR area cancelled through lack of crew ... guess where

 
Cancellations to services between Reading and Newbury
Due to a points failure between Reading and Newbury some lines are blocked.
Train services running to and from these stations will be cancelled, delayed or diverted between Reading and Taunton. Some stations between Reading and Taunton will not be served. Disruption is expected until 13:15 29/04.

A few diverted trains resulting.