Announcement

Collapse
No announcement yet.

Smart Inverters

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Smart Inverters

    There's an interesting article in the new issue of IEEE Spectrum about upcoming standards for smart inverters in California.

    California is apparently going to require grid-tied inverters to not just inject power onto the grid, but also actively help stabilize voltage and frequency. I don't live in California or pay much attention to inverter requirements, so this is the first I'd heard about it.

    Also interesting: according to the article, at least some existing inverters will be upgradable through a firmware upgrade to take on these new functions.
    16x TenK 410W modules + 14x TenK 500W inverters

  • #2
    Originally posted by pleppik View Post
    There's an interesting article in the new issue of IEEE Spectrum about upcoming standards for smart inverters in California.

    California is apparently going to require grid-tied inverters to not just inject power onto the grid, but also actively help stabilize voltage and frequency. I don't live in California or pay much attention to inverter requirements, so this is the first I'd heard about it.

    Also interesting: according to the article, at least some existing inverters will be upgradable through a firmware upgrade to take on these new functions.
    If I understand, the inverters may be used to help correct power factor. I think they
    are saying, this can even be done without PV input. Sort of a capacitor emulator I
    guess. But that would probably hurt their own efficiency, esp someone like me with
    a (well loaded) 600' loop of wire to the meter.

    As for correcting voltage and frequency, I don't see how solar is big enough for effect.
    Frequency slips when all the generators have their throttles at max, running no reserve.
    Like a harness of 1000 of horses pulling together; one more horse hitching up isn't going
    to get things moving faster. Bruce Roe

    Comment


    • #3
      Originally posted by bcroe View Post
      As for correcting voltage and frequency, I don't see how solar is big enough for effect.
      There is not enough out there to make a blip on the radar. Kind of like peeing on a forest fire. Someplace like Hawaii where there is a significant percentage of solar, then it is possible. Problem I see is it all has to be synced and linked up to a central command. Meaning Brig Brother with full view and control of your equipment.
      MSEE, PE

      Comment


      • #4
        I don't see how small home owner string inverters will be able to provide any type of grid stabilization with respect to voltage and freq.

        As for Power Factor, most homes don't have low values due to the lack of any large horsepower induction motors being used. Industrial and commercial installations are already installing PF correction mostly due to penalties that the POCO include in their rate structure so you might see some additional PF mitigation if they also install large PV arrays on their site. They will need to be careful of the side affects of harmonics that can cause the PF correcting capacitors to fail.

        What I see is that as more and more RE is added to the grid the Utilities will have to install some type of energy storage system (like batteries) at critical points to help stabilize V & Hz. It will not be cheap but might be required for them to meet their commitment of a consistent and stable power source to their customers. Just means an increase of rates to everyone.

        Ok. I read that article and it looks like Enphase has reprogrammed string inverters to be less "sensitive" to grid power quality issues so the do not disconnect as quickly using their "anti island" protection. That may help improve somewhat the grids ability to maintain a consistent power flow but will not eliminate RE outages when clouds go overhead. Also adding Reactive power generating devices to the inverter to "off set" low PF will be very hard to control considering the number of hardware points that would require split second changes to keep the voltages from spiking or dropping.
        Last edited by SunEagle; 02-16-2015, 10:39 AM. Reason: Added last sentence

        Comment


        • #5
          Originally posted by bcroe View Post
          If I understand, the inverters may be used to help correct power factor. I think they
          are saying, this can even be done without PV input. Sort of a capacitor emulator I
          guess. But that would probably hurt their own efficiency, esp someone like me with
          a (well loaded) 600' loop of wire to the meter.

          As for correcting voltage and frequency, I don't see how solar is big enough for effect.
          Frequency slips when all the generators have their throttles at max, running no reserve.
          Like a harness of 1000 of horses pulling together; one more horse hitching up isn't going
          to get things moving faster. Bruce Roe
          But it sounds real nice and all the boys and girls on the green sites go Ohhhhhh! So Coooool!
          [SIGPIC][/SIGPIC]

          Comment


          • #6
            Update: cpuc.ca.gov/General.aspx?id=4154 says there's a "smart inverter working group" that continues to meet.

            Also, it seems they're getting ready to set efficiency standards for plain old inverters, see energy.ca.gov/appliances/2017-AAER-06-13/17-AAER-13.html

            The one document in that docket so far is a response from utilities with their understanding of the inverter market, docketpublic.energy.ca.gov/PublicDocuments/17-AAER-13/TN219245_20170616T164459_California_Investor_Owned _Utilities_Comments_Response_to_Invita.pdf
            17kw. I like science, but I'm no expert.

            Comment


            • #7
              Originally posted by DanKegel View Post
              Update: cpuc.ca.gov/General.aspx?id=4154 says there's a "smart inverter working group" that continues to meet.

              Also, it seems they're getting ready to set efficiency standards for plain old inverters, see energy.ca.gov/appliances/2017-AAER-06-13/17-AAER-13.html

              The one document in that docket so far is a response from utilities with their understanding of the inverter market, docketpublic.energy.ca.gov/PublicDocuments/17-AAER-13/TN219245_20170616T164459_California_Investor_Owned _Utilities_Comments_Response_to_Invita.pdf
              I hope the POCO's get their act together concerning inverter technology. Right now most of the ones in MA require some pretty crazy grounding hardware to reduce Fault current levels. The problem is that they do not recognize immediate shut down and isolation of the inverter if there is a ground fault on the primary grid supply. They choose to treat it as a generator which tends to coast to a stop and can still inject voltage onto the grid increasing the fault currents. PIA and IMO another barrier to a third party installing a large solar grid tie array.

              Comment

              Working...
              X