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Planned Power Outage Last Night... Question

Sep 24, 2015
814
684
San Diego (Oceanside)
Last night we had a planned power outage scheduled to begin between 10-11p until 6am. PW's were charged and set to go. I usually am in self powered most of the time and was last night after about 8pm. Yesterday's data in the app confirms this. Since the house was already on battery, I expected a whole not of nothing to happen. Instead, at 10.30, my UPS's around the house beeped briefly and I saw my cable box and tuning adapter rebooting which was plugged directly into a non UPS power center then to the wall.

If the PW's were already supplying power to the house, why was there a brief interruption? I expect this if the power goes out during the day when solar is powering the house and the PW's have to suddenly take over and shut down the inverters, but since PW was already supply power to the house, regardless of grid status, why was this noticeable?

Another oddity, the notification of the outage said PW was 44% charged. I have two and they were at 88%.
 

BrettS

Active Member
Mar 28, 2017
2,109
2,512
Orlando, FL
When the grid is up your system needs to synchronize itself with the grid frequency and voltage, however, this means that if there are some fluctuations in the frequency or voltage then the system will stay synchronized with those fluctuations (for a short time). This is called ride through and it’s an attempt to prevent hundreds or thousands of houses that are supplying solar to the grid from all disconnecting from the grid simultaneously if there is a small fluctuation in the frequency or voltage. That could turn a small fluctuation into a much larger problem. If the problem continues, however, then your system will disconnect from the grid.

If the power cuts off cleanly then you shouldn’t really be able to notice the transition. However, if the power cut off wasn’t clean then your system may have attempted to ride through the disturbance, which may have been enough to upset the UPS’s and restart your cable box before your TEG disconnected from the grid and created it’s own micro grid with it’s own reference frequency and voltage.
 

aesculus

Still Trying to Figure This All Out
May 31, 2015
4,377
2,486
Northern California
I wonder how much cap banks and voltage regulators, especially if you are near them, contribute to a "dirty" disconnect?

It sounds like the power, for a fraction of a second or more, was not clean as @BrettS stated and that caused your system to go into it's safe mode.

When you throw the switch at home to disconnect from the grid there is nothing on the grid side to "dirty" up the power like there could be in real life.
 
Sep 24, 2015
814
684
San Diego (Oceanside)
When the grid is up your system needs to synchronize itself with the grid frequency and voltage, however, this means that if there are some fluctuations in the frequency or voltage then the system will stay synchronized with those fluctuations (for a short time). This is called ride through and it’s an attempt to prevent hundreds or thousands of houses that are supplying solar to the grid from all disconnecting from the grid simultaneously if there is a small fluctuation in the frequency or voltage. That could turn a small fluctuation into a much larger problem. If the problem continues, however, then your system will disconnect from the grid.

If the power cuts off cleanly then you shouldn’t really be able to notice the transition. However, if the power cut off wasn’t clean then your system may have attempted to ride through the disturbance, which may have been enough to upset the UPS’s and restart your cable box before your TEG disconnected from the grid and created it’s own micro grid with it’s own reference frequency and voltage.

Thanks for the explanation. It would be interesting to see the logs of the event. Too bad they're not available from the PW.
 

gpez

Member
Apr 25, 2019
653
530
USA
Thanks for the explanation. It would be interesting to see the logs of the event. Too bad they're not available from the PW.

In my experience Tesla support has access to at least some of the logs and possibly could shed some light on what happened if you called an asked. YMMV.
 

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