Path: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail
From: Martin Brown <'''newspam'''@nonad.co.uk>
Newsgroups: sci.electronics.design
Subject: Re: Grand Apagon - Electricity (not) in Spain
Date: Thu, 8 May 2025 11:57:39 +0100
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On 08/05/2025 00:01, Don Y wrote:
>>>>> Much like me having carrier doesn't tell me the extent of
>>>>> my "reach", here.
>>>>
>>>> Well, the power outage was "total". :-D
>>>
>>> Yeah, but you don't know which services (up the chain) may
>>> have their own *local*/private backup systems.  E.g., I doubt
>>> your hospitals were without power (?)  The extent of backup
>>> beyond that would be something you'd have to know, in advance.
>>
>> If the fibre goes direct to the exchange, they had backup power. 
>> However, if the distance is great and they have to reconstruct the 
>> signal with some kind of optical amplifier, then I don't know. The 
>> distance is about 2.5 Km.
> 
> But where can exchange traffic go?  See what I mean?  Anyone that
> you want to contact (and everyone along the way) must be "up".

That was the original point of ARPANET then EPSS and later the internet. 
Packet switching means that any route to the destination at all will do.

I'm told that my fibre feed is passive optical connectors and splices 
all the way back the regional exchange about 12 miles away. My local 
exchange was about 5 miles away and a so-called exchange only direct 
line (which meant that ADSL 2+ was the limit for me prior to FTTP).
> 
>> My mobile phone worked all the day, I could send and receive whatsapp 
>> messages.
> 
> Are those processed "locally"?

Mobile phone masts here typically have a lifetime of about 8-40 hours 
after power failure depending on how heavily they are being used. 
Backhaul presumably is optical or microwave.

Most powercuts tend to be fairly local round here - a regional powercut 
or a national one requires something truly catastrophic to happen.

I can only recall one UK powercut in that league in the past half 
century (August 9 2019). Of course it directly affected the densely 
populated affluent regions London and the South East. Therefore it was 
much more newsworthy than if it had affected the remote Scottish 
Highlands where weather induced powercuts are quite common.

The recent big one at Heathrow didn't affect all that many people 
although it did take down the whole airport which shows remarkably bad 
contingency planning - it should have had supply redundancy and the 
ability to switchover to it before the diesel generators ran out of 
fuel. Heads should roll over them having to shut down completely.

>> I have a small computer doing server things, and it tried to email me 
>> as soon as the UPS said it was running on battery. That email did not 
>> reach me till the power came back; this could be that the fibre went 
>> OOS, or that the UPS at my router went down instantly. I do not know.
> 
> Doesn't your UPS deliver log messages (to a syslog server or data
> dumps to an FTP service)?
> 
> I have each of mine configured to give me summaries of power consumption
> and line conditions each minute.  And, use a syslogd on that same server.

I only log external power failures. Kitchen appliance clocks all reset 
when we lose power for more than a couple of seconds.

>> I'm considering replacing the UPS at my router. Some UPS "destroy" the 
>> battery too fast.
> 
> Yes.  Rather than spend time investigating it, I've taken the approach
> of just rescuing batteries to replace those that have been "cooked".

That is a feature of UPS design that specsmanship to get the longest run 
time for the sales datasheet means that they cook their batteries. I 
have seen them swell to the point of bursting inside a UPS. Thick rubber 
gloves needed to remove the remains. Support metalwork was a real 
corroded rusty mess but electronics above it remained OK.
> 
> I suspect the problem (rationalized by the manufacturers) is trying to
> bring the battery back to full charge ASAP -- as well as keeping the
> highest state of charge that the battery can support.

Which taken to extremes is very bad for battery life.

> Charging at a slower rate and to a lower float voltage would
> compromise the UPS's availability -- but provide less maintenance costs
> (of course, the manufacturer wants to sell you batteries, so you
> can see where their priorities will lie!)

They really think I'm going to buy their vastly overpriced replacements?

-- 
Martin Brown