Show Posts
|
Pages: [1] 2 3 ... 351
|
1
|
All across the Great Western territory / The Wider Picture Overseas / Re: Spain / Portugal power outage
|
on: April 29, 2025, 23:31:53
|
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.
|
|
|
2
|
Sideshoots - associated subjects / Campaigns for new and improved services / Re: Shipping services across the Severn
|
on: April 29, 2025, 20:31:25
|
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.
|
|
|
4
|
All across the Great Western territory / The Wider Picture Overseas / Re: Spain / Portugal power outage
|
on: April 29, 2025, 18:21:56
|
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.
|
|
|
6
|
Journey by Journey / Transport for London / Re: Intoxicated person plan needed on Tube - coroner, April 2025
|
on: April 26, 2025, 04:04:44
|
This is very sad, but I feel that the deceased was largely to blame for this accident. Learning points include, do not get stupidly drunk. After moderate drinking be especially careful near trains and near roads. There seems little that London transport could have done to prevent this accident, perhaps exclude those who are very drunk from underground stations !
I have been known to drink too much, but never to the point of placing myself or others in significant danger.
|
|
|
9
|
All across the Great Western territory / The Wider Picture in the United Kingdom / Re: "Long Products"... Steel Rail.
|
on: April 14, 2025, 15:41:35
|
Electric arc furnaces are very useful for recycling of scrap steel, but are not used for production of new material from iron ore. They also consume a great amount of electricity, and there are already concerns as to the adequacy of UK▸ electricity supplies. UK electricity is very expensive, and is arguably overpriced, this wont encourage widespread use.
Arc furnaces are also a very "disturbing" load and often require expensive grid upgrades so as to minimise adverse effects on existing customers.
|
|
|
10
|
All across the Great Western territory / The Wider Picture in the United Kingdom / Re: "Long Products"... Steel Rail.
|
on: April 13, 2025, 18:34:46
|
Doubts have been raised as to the availability of suitable and sufficient coke to run the blast furnaces. Whilst HMG have guaranteed payment for the fuel, that does not ensure physical availability. I doubt that coke already in transit in russian or chinese ships will be available, expect mechanical breakdowns, delays, diversion to other ports or non compliant paperwork. Air freight might even have to be used. One delivery had been made to a customs secured site, awaiting payment - which I guess has now been made since legislation has completed Was not aware of that, thanks for the update.
|
|
|
11
|
All across the Great Western territory / The Wider Picture in the United Kingdom / Re: "Long Products"... Steel Rail.
|
on: April 13, 2025, 16:35:33
|
Doubts have been raised as to the availability of suitable and sufficient coke to run the blast furnaces. Whilst HMG have guaranteed payment for the fuel, that does not ensure physical availability. I doubt that coke already in transit in russian or chinese ships will be available, expect mechanical breakdowns, delays, diversion to other ports or non compliant paperwork. Air freight might even have to be used.
|
|
|
14
|
All across the Great Western territory / The Wider Picture in the United Kingdom / Re: Monmouthshire and Brecon Canal - water shortage, March 2025
|
on: April 06, 2025, 04:08:29
|
Each time that a lock is used, water runs down hill, and a continual supply of new water is therefore needed to the upper reaches of the canal. Could some of this water not be re-used ? It should be relatively simple to install a pipeline along the canal so as to pump some water from the bottom of the canal to the pound or reservoir at the top. There is no need to return ALL the water to the top, just enough to avoid shortages. Either use off peak grid power for this pumping, and pump only in the off peak hours at a much reduced cost, or alternatively power the pumps from an array of PV modules installed for the purpose, and pump only during hours of sunlight.
|
|
|
|