Re: Grand Apagon - Electricity (not) in Spain

On Tue, 29 Apr 2025 20:32:22 +0100, Martin Brown
<'''newspam'''@nonad.co.uk> wrote:

On 29/04/2025 18:52, Don Y wrote:

On 4/29/2025 8:07 AM, Martin Brown wrote:

>

They try very hard not to mention the fact that their load shedding
algorithm was shedding a lot of local solar PV generation along with
the load so that it was playing catch up and never quite getting there.

 
Can they disconnect individual residential installations?

>
In principle they can disconnect any residential installation with a
smart meter (although they are normally prohibited from doing so). And
anyone with a SMETS1 "smart" meter is wide open for a bad actor to flip
their power on and off deliberately to bring the UK network down.
>
https://www.bbc.co.uk/news/technology-22608085
>
Unclear if the smart meters from that era that have become disabled by
the customer changing supplier are still a hacker security risk or not.
State actors would have no trouble hacking them...
>
Some university researchers had no real bother!
>

Or, just solar "farms"?

>
They can drop out entire blocks of switchgear to take a given region or
zone offline (as would happen if a fault condition trips a breaker).
>
The big problem on a really sunny day is that an individual house roof
4kW PV installation in late afternoon in the UK will be potentially
exporting all of it to the grid. That is about 20-30 houses worth of
electricity for each solar roof.
>
They drop say 100MW of load or approx 500k houses @ 200W but with 2% of
them generating 4kW then they also drop off 40MW of local generation.
>
So the net load shedding is only 60MW which isn't enough to restore the
balance and then the cycle repeats until it hits the low frequency total
panic limiter. UK stopped it spreading by manual override dropping more
than the algorithm wanted but leaving a big area without power.
>
It didn't help that by the time they did that the low frequency had put
a lot of electric trains into a disabled state requiring a hard reset by
a qualified service engineer visit and at random positions on the
intercity train lines. The guys who could do that were in short supply.

Gosh, multiple layers of bad engineering. All that stuff used to work
30 years ago.