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SolarEdge PV system Iso[KOhm] 4131.6

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  • SolarEdge PV system Iso[KOhm] 4131.6

    Hello,

    Please bear with me. I need to explain my setup first.

    I am an owner of the soar panel system. The system went live in mid 2016 and since that time the installer is no longer in the business. For the most part the system runs without any issues.

    Original system has 34 - 300W panels connecting to SolarEdge inverter.

    The design looks like this

    solarpanellayout-orgsm.jpg

    I installed 5 more panels. I used IronRidge rails and brackets, P300 SolarEdge Power Optimizer and 250W Panels. I tried to follow installation codes as close as possible, so please dont rif on me for this.

    7773691249279647102SM.jpg

    I ran the 10 gauge solar PV cable and a copper ground inside the flex electrical conduit against the walls and connected to the power optimizer on the panel 1.2.14.

    20200309_162823sm.jpg
    I checked to make sure that the (+)(-) from the new array connects to the (-)(+) of the Power optimizer on the 1.2.14 panel.

    This image is just a drawing, the new panels have not be added to the site in the solaredge portal

    solarpanellayout1sm.jpg


    After performing the initialization and pairing all 39 power optimizers were found, however, it also display Isolation error 2x19. The system starts up, initializing then restarts again.

    25 2x19 121 8x58 Isolation Fault PV solar array is not properly isolated from ground earth. Check the PV installation for isolation problems and ground leakage. Only a certified PV installer must fix the faulty string before connecting it to the inverter. ... Turn OFF the inverters in the site and verify AC grid voltage.

    After I unplugged the new array from the system. (I unplugged the cable from panel 1.2.16 and closed the loop by connecting the cables together).

    After performing the initialization the system started and were reporting 34 panels. However, while researching the "isolation error" I found out that I can perform Isolation test in the inverter. The test shows the following:
    20200310_090713sm.jpg

    From what I gathered the Normal KOms should be 11000 and percentage should be 50. So even with out the new array there is a grounding issue somewhere. But from what I can tell the original system works OK. I ran this test fir the first time and only just found out about it. I would not even found out there is a problem if wasn't for me try adding additional panels.

    I called solaredge and the tech told that the issue could be in many different places and I would need to get an installer to run diagnostics. Since my installer no longer in business...



    1. How serious is this issue?
    2. Does it diminishes the system performance in anyway?
    3. Can I somehow diagnose it my self?
    4. What are my options at this point?

    There not that many solar companies in my area that do maintenance. The once that do, charge $199 just to come out and do diagnostics, there is additional charge to fix it. Also since I am trying to add additional panels myself, the new installer may not want to touch the system.


    Regarding the new array

    1. How do I test to see where is there grounding issue?


    I know there are many questions here. I would appreciate your suggestions.

    Thank you




  • #2
    Originally posted by astroprojector View Post

    1. How do I test to see where is there grounding issue?
    I would check subsections of the arrays.
    To start with, it looks like you have 2 strings - I'd hook up only one of them and check. Then I'd hook up the other and check.
    And it's possible that you have multiple problems that slowly add up. So you might have some with each and together you're getting over the limit.

    I'd also look for any physical damage (ex. spot where a cable has been damaged and is touching a rail (which is grounded))

    I'd also look at everything new that was added - it sounds like you didn't quite remove all the new stuff. You still have some of the new wiring in the loop.

    Comment


    • #3
      Originally posted by astroprojector View Post
      I ran the 10 gauge solar PV cable and a copper ground inside the flex electrical conduit against the walls and connected to the power optimizer on the panel 1.2.14.
      FWIW, I'd replace that flex with EMT. EMT and a bender doesn't cost much. And it'll look a lot better.


      Comment


      • #4
        I would agree with foo1bar 100%. Check the isolation value on each of the 2 strings separately. Then you will want to check all of the wires and make sure there is no damage. Also check to make sure the wire that go from the last optimizer to the inverter are THWN rated ("W" means water resistance). If they are not, then any moisture can cause isolation issues in the insulation.

        Lastly, I'm assuming you confirmed that you don't have too many modules in the string now that you added 5 more?

        Comment


        • #5
          Your indicted ground leakage seems to be enough to be detected, but not enough to affect
          operation. With twice as many panels and extensive wiring including buried, my system at
          operating voltage measured over 100,000K ohms. Yours indicates 11,000K as a minimum,
          4100K ohms detected. The risk is that a fault will continue to degrade later.

          Agree here, completely disconnect half the system and see if the leakage goes away. This
          includes disconnecting the wiring leading to the inverter, which might contain the fault. Do
          one side and the other to narrow it down, then keep adding/removing smaller sections till
          you are on top of the fault. Do not open any conducting DC connections to avoid arc damage.
          I try to do wiring work at night, but opening up the AC line connection can stop currents.
          good luck, Bruce Roe
          Last edited by bcroe; 03-12-2020, 11:47 AM.

          Comment


          • #6
            Originally posted by bcroe View Post
            Do open any conducting DC connections to avoid arc damage.
            I try to do wiring work at night, but opening up the AC line connection can stop currents.
            good luck, Bruce Roe
            I'm assuming you mean "Do Not".
            But with SolarEdge it's not really an issue. As long as the inverter is off, the optimizers only put out 1V.

            Comment


            • #7
              Originally posted by emartin00 View Post

              I'm assuming you mean "Do Not".
              But with SolarEdge it's not really an issue. As long as the inverter is off, the optimizers only put out 1V.
              Yes, but I can not immediately edit a message because this reflector will put it on
              hold for moderation. Have to wait a day. thanks, Bruce Roe

              Comment

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