Incorrect data representantionafter blackout in spain

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Hi

I’m living in North of Spain where, as you probably know, suffered a massive blackout last monday. In our home the blackout lasted form 12:30 PM until 17:30 PM aproximately.

Today I wanted to check how my energy metering devices had measured the event and what I’ve encontered bothers me.

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In the image you can see the frequency measured in my MCB . As you can see the device detected correctly the frequency drop at 12:30 but as you can see there are measurements until 3:30 PM. After that there is a gap of 5 hours until 8:30 PM.

At first I thought it was a problem with this variable, but it happened with all of them, for example, here you can see the processor temperature in the system monitor:

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Is like the data has shifted 3 hours after the blackout and the power restoration.

I can guess now is difficult to solve but I would like to understand how it happened ?

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Are you running HA on a Raspberry Pi? Does it have a battery-backup clock module (RTC) installed?

If there is no RTC on a Pi, my understanding is that it uses the last known running date as its current date when it reboots until it can get the time via the Internet (NTP).

If the Internet was delayed in recovering from the nation-wide blackout, the large gap on all of your graphs may be from when the clock finally set itself and the time instantly jumped five hours ahead…

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Ok, That would explaing everything.

yes, I’m using raspberry Pi 4B without RTC. And I’m sure that after getting the power back the router was without connection for a few hour so that would cause the incorrect time for data until the internet connection was back and the RbPi corrected its hour

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