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From: Martin Brown <'''newspam'''@nonad.co.uk>
Newsgroups: sci.electronics.design
Subject: Re: The Spanish Grid Drop-out - recently released information.
Date: Thu, 15 May 2025 14:18:14 +0100
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On 15/05/2025 13:43, Jeroen Belleman wrote:
> On 5/14/25 23:35, Don Y wrote:
>> On 5/14/2025 7:16 AM, Glen Walpert wrote:
>>>
>>> SCADA is used to monitor and control the grid, where control is done in
>>> real time by adjusting the set points for real and reactive power at all
>>> controlled power sources.  A small percentage of sources being
>>> inaccessible degrades control by an insignificant amount.

I'll believe it is used to monitor the parameters at key locations in 
"realtime", update set points and try to reset tripped breakers.

>> "Real-time" means different things to different applications.
>>
>> I took Theo's upthread suggestion to mean broadcasting a *reference*
>> that all genertors would track -- instead of using the actual power line,
>> itself.  I.e., the spain event could have been avoided if such a 
>> broadcast
>> reference were used by each generator DISREGARDING THE ACTUAL POWER 
>> SIGNAL.
>> [...]

> Sounds like a perfect recipe to blow things up. No individual
> generator can pretend to force the grid. Either they track
> or they trip.

Pretty much guaranteed to cause trouble when the national grid is of a 
size and power level such that it behaves like a true transmission line 
even at 50/60Hz. ISTR it limits supergrid power handling to ~3GW max.

UK's peak N-S flow is limited by a "thermal constraint" on some 
insignificant location not far from where the new DC interconnector 
comes onshore. No explanation is given as to what that really means.

> Driving power into the grid only makes sense in reference to
> what is happening at the injection point.

Indeed. And smaller generation systems can just get crushed like flies 
if they try to stop a rampaging elephant as big GW systems drop offline.

If the system did fail due to local over voltage excursions somewhere 
and then failed to become stable again after a few suppliers dropped out 
then their network stability analysis must be appallingly bad.

-- 
Martin Brown