Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail
From: Don Y <blockedofcourse@foo.invalid>
Newsgroups: sci.electronics.design
Subject: Re: Grand Apagon - Electricity (not) in Spain
Date: Tue, 29 Apr 2025 17:07:10 -0700
Organization: A noiseless patient Spider
Lines: 40
Message-ID: <vurpjq$2ut4u$1@dont-email.me>
References: <vuqgef$1of93$1@dont-email.me> <vuqogf$1vlqj$1@dont-email.me>
 <vuqq0c$217v6$1@dont-email.me> <vur3l4$2avav$1@dont-email.me>
 <vur9g9$2glaf$1@dont-email.me>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Wed, 30 Apr 2025 02:07:24 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="c3950f48bb4044cf2ff1ab314334dc69";
	logging-data="3110046"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX186t2J2or1oEdOhJSBBCba7"
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:102.0) Gecko/20100101
 Thunderbird/102.2.2
Cancel-Lock: sha1:ZxXp6ZC7IygSX9OZntuEcyqitgA=
In-Reply-To: <vur9g9$2glaf$1@dont-email.me>
Content-Language: en-US
Bytes: 2937

>> 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.

Huh?  A single residential PV is enough to *power* 20 homes?
A 4-5KW installation would barely cover the home on which
it was sited.

E.g., our "average" (24/7) load is about 1KW.  Of course, that
neglects the peaks that we see OFTEN throughout the daylight
hours (night load is relatively small -- a few LED lights
plus my computers)

> 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.

The 200W figure is mystifying.

> 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.

Hence my comment about dropping individual loads (cogenerators).

> 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.

"Unforeseen consequences".  A reason simpletons can't deal with
complex systems.