Solar Panel - Unusual Behaviour

hashtagbargain on 22/10/2023 - 02:20
Last edited 27/10/2023 - 16:34

Today I found out that my electric solar panel system of 5 kw installed 3 years ago had not generated any energy between 2 pm and 5.30pm, I’ve never seen it do that before. No idea this could happen, anyone have any idea how/why?

https://files.ozbargain.com.au/upload/29505/107532/img_0702.…

It is a sungrow inverter and longi panels if it helps.

27 Oct 2023 Edit: looks like it may have been temporary communication issue (possibly on the server side) as the graph now seems complete and missing data present in the sungrow app. I also checked the data from lumo energy and they seem to have logs of export. I’m grateful it isn’t a failure of any system.

Case closed, thanks for everyone’s inputs on this one!

Home & Garden Solar Energy System

Comments

  • iforgotmysocks on 22/10/2023 - 02:41
    +9

    Being in Melbourne your system may joined a union and elected to strike over poor working conditions

  • Euphemistic on 22/10/2023 - 06:13
    +3

    Eclipse?

  • SBOB on 22/10/2023 - 06:14
    +8

    High grid voltage would be a possible cause, assuming your actual daily total aligns with it not generating power rather than just being a logging issue

  • Muzeeb on 22/10/2023 - 06:25
    +3

    Hashtagglitch

  • Nugs on 22/10/2023 - 06:54
    +3

    Were you at home? Was there power outage?
    .

    • hashtagbargain on 22/10/2023 - 10:43

      Yeah I was at home but it was a sunny day. I was curious about the solar generation so I looked into the graph.

      No power outage, but a possible power degradation (low/hi voltage) as some here have pointed out.

  • lgacb08 on 22/10/2023 - 07:38
    +3

    What was the network voltage during those times? It might shut down due to high grid voltage. What was the graph like on 2 days before?

    • hashtagbargain on 22/10/2023 - 10:43

      The graph on other days has been as expected. I’ll try to find out about the grid voltage.

  • noz on 22/10/2023 - 07:41
    +1

    Maybe your DNSP was doing some curtailment testing. I wouldn't worry about it too much unless it happens again soon.

  • geekcohen on 22/10/2023 - 07:44
    +5

    A few questions:

    • Where are you getting this data? From your inverter portal online?
    • Is this happening every day or just the one day?
    • If you are looking online, maybe the portal had an outage/maintenance so it didn't record data?
    • Internet outage? Possibly your inverter couldn't upload data because you had an internet outage?
    • Was there a grid outage? (as per one of the above comments)
    • hashtagbargain on 22/10/2023 - 10:48

      Hi Cohen

      • Data is from my inverters app, it gets uploaded which leads to a possibility that it might have been an internet issue during this time (perhaps on their end)
      • just one day, I went through many days in the past and nothing like this shows up.
      • the portal doesn’t say about outage
      • possible, but there was no actual internet outage on my end (my cameras were streaming fine during this window)
      • grid outage not possible (power didn’t go out) but degradation possible.
      • geekcohen on 23/10/2023 - 08:45
        +1

        Data is from my inverters app, it gets uploaded which leads to a possibility that it might have been an internet issue during this time (perhaps on their end)

        Very possible, could've been a portal outage, maintenance, who knows.

        just one day, I went through many days in the past and nothing like this shows up.

        Okay, that is interesting.

        the portal doesn’t say about outage

        You might not know about it being it was in the past.

        Overall, seeing as it is a once off, I would just monitor and see it if to continues.

  • roonie on 22/10/2023 - 09:27
    +2

    Was your internet down?

    • hashtagbargain on 22/10/2023 - 10:38

      No Internet outage as far as I know.

    • Hansi on 22/10/2023 - 13:31
      +1

      Could also be issues with the WiFi, not just the internet. I changed my WiFi and had the same gap on my inverter for the exact time it wasn't able to connect to the internet. I assume it can only record live, not store locally in case of an outage.

  • GordonD on 22/10/2023 - 09:36
    +1

    If it only happens once, ignore it.

    If it keeps happening, get back to us and we'll tell you what to look at.

  • knasty on 22/10/2023 - 09:44
    +2

    If the power goes out you get a flatline. I had exactly the same thing on mine the other day with a random blackout in the area.

  • JimmyF on 22/10/2023 - 10:14
    +1

    had not generated any energy between 2 pm and 5.30pm, I’ve never seen it do that before. No idea this could happen, anyone have any idea how/why?

    Was this a once off event?

    Had you been home at the time? Could it have been a power outage?

    Otherwise high (or low) line voltage from the grid will cause the inverter to stop producing power, but it's rarely low, but high voltage as the grid rises with all the excess solar being pumped into it.

    Are you on any demand response plans?

    If it is a once off thing, then meh one of the above issues was the cause. If it happens all the time, then you need to investigate. The inverter should tell you on the front if it has a screen what the fault is, otherwise connect to the inverter and see what the issue is.

    If its high voltage, you need to log a fault with the grid people in your area.

  • resisting the urge on 22/10/2023 - 11:03
    +1

    You should be monitoring the supply voltage to the inverter. Grid voltage will be lower, but only as far as the function of line resistance from your inverter to the pole.

    If high voltage across your local grid is the cause of the inverter shut down (the instructions/manufacturer/distributor/vendor should tell you what the maximum allowable supply voltage before the inverter protection triggers a generation disconnect/shutdown. When it happens, the inverter should show the error on screen, and log the nature of the fault.

    Bear in mind that 2-5pm may be the hottest time of the day, so it is not only the time when your local grid voltage is likely to peak, it is also the time of day that the inverter will be hottest (I assume it is not in the sun, as no inverter should be installed in direct sun) as thermal overload can also cause internal protection to trigger. Over time, grid voltages in many segments have risen, and the local grid managers may not have addressed this in your area yet. When it happens, for all the installations in a given street, the protection on one or two will begin to trigger first, then more. These are the ones that have the highest resistance between their inverters and their pole connections, which to some degree can be reduced by the owners if they use the thickest possible wire connecting their inverter- assuming there is enough of it to make a difference (when situated right beside the switchboard and meter, they are very short). Some are 2.5mm cables, and can often be upgraded quite cheaply to 10mm. For example I recently reduced the voltage to 2x5kW inverters by 1.5V by going from 6mm to 10mm (during peak generation).

    Maybe you have logs of internal temperature too? ;-)

    The only other thing it could be is PV output exceeding an input limit- either voltage, or current. Given its not done this when new, this is unlikely, but it could be that there is a fault in the array that is upsetting the DC output so much that the inverter notices a fault on one or more of the arrays. Again, this should get logged in the inverter.

    So it's time to look up the logs, compare to supply voltage, and find the cause. And let us know!? :-)

    • GordonD on 24/10/2023 - 18:42
      +1

      If high voltage across your local grid is the cause of the inverter shut down (the instructions/manufacturer/distributor/vendor should tell you what the maximum allowable supply voltage before the inverter protection triggers a generation disconnect/shutdown.

      No, this is not determined manufacturer/distributer/vendor, it is specified by the power company in the state. And all inverters are set to that number. There is one number which if the mains is over that the inverter won't try to connect. There is another number which if the mains is over that the inverter will disconnect.

      • resisting the urge on 25/10/2023 - 20:11
        +1

        I can't figure out what you mean.

        The nominal mains supply voltage in Australia has changed. AS 60038 now mandates:
        230V single phase with +10% to –6%
        400V three phase with +10% to –6%

        These are not absolute, but instead the standard allows for occasional spikes which may allow everyone off the hook when they get things wrong re network topology, expected demands and available generation.

        The old obsolete Australian Standard AS 2926 was:
        240V single phase +/- 6%
        415V three phase +/- 6%

        But grid voltage can spike if is poorly managed in a particular area- this happens when everyone has installed large amounts of solar, the sun comes directly overhead in summer, and the current being exported from the circuit is higher than has been allowed for in the network design.

        For more info: https://electricalconnection.com.au/when-voltage-varies/

        • GordonD on 26/10/2023 - 13:45

          Nothing to do with the nominal mains voltage going down from 240V to 230V, except that in various parts of Australia the power companies didn't reduce the actual mains voltage, so the voltage at which the inverter is required to shut off and stop generating power isn't far above the normal mains voltage.

          I'm in an area where the normal mains voltage was 248-250V, which meant it only took a cool sunny day for the amount of rooftop solar being generated, with none being consumed locally, to push the mains voltage to 254V, and everyone's inverters shut down. And the last ones to start up in the morning to not even try to connect to the grid because the mains voltage was already too high.

          See if you can understand this article:

          https://support.solarquotes.com.au/hc/en-us/articles/1150017…

          • resisting the urge on 27/10/2023 - 10:52

            @GordonD: "Nothing to do with the nominal mains voltage going down from 240V to 230V" which is not what I said, at all.

            And now you're saying what I and so many have suggested was the fault. The only thing I can think of that would cause any confusion here is that I call mains voltage (local) grid voltage- the voltage at the consumer supply point.

            At no point was I saying nominal mains voltage to be a problem; only that a regular spike that might cause an AC over-voltage protection trip.

  • doctordv8 on 22/10/2023 - 16:59
    -3

    Curly one.

    What did your installer say? Has it been on the spot diagnosed?

    Please advise.

    • doctordv8 on 26/10/2023 - 12:21
      -2

      3 Negs… Why now? 3 answers required or are you cowards as well?

      • doctordv8 on 27/10/2023 - 12:53
        -1

        Mods, me thinks we have cowards leavings Negs without any reasoning.

  • noob999 on 23/10/2023 - 13:21
    +2

    Most PV inverters communicate directly to the cloud an do not buffer or locally store the data… Sounds like an internet or server outage during this time.

  • Pascal on 24/10/2023 - 19:19
    +2

    Does it happen every afternoon? I once had a dead possum stuck under my panels. No production in the afternoon over days. My theory is that the possum body inflated a bit in the afternoon and shorted the system. Gosh, that was $200 well spent on the possum removal, beyond a mess.

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