Solar inverter failure

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  • Aia
    Aia Posts: 13 Forumite
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    edited 12 January 2018 at 7:04PM
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    Dave_Fowler wrote: »
    At 249V, Vgrid is higher than normal. Can it be that when you start to generate power via the inverter, the mains voltage rises still further and the inverter is registering a fault because of excess mains voltage and the relays disconnect the input?

    If the inverter operates without an error light when there is no PV voltage (DC off, AC on) and also operates with no error light with DC on and AC off, I would suspect there is an over-voltage condition on the mains grid input.

    Dave F

    it crossed my mind as well. Luckily in 2016 I took a picture of it , and it showed a voltage of 249V, and was operating normally.
    on the 6th of January it showed 243.7V but still showed a fault. In Manchester we seem to have a higher voltage than everyone else. (was taught 230V in school)

    "If the inverter operates without an error light when there is no PV voltage (DC off, AC on)"
    in this situation, the display is off and I think there was no lights on at all.

    I had crawled up in to the attic, (after borrowing a ladder again) and it had become dark outside, so there was no DC voltage. The display was off and from memory there were no light on. The AC switch was on when I went up to have a look.
  • ard123en
    ard123en Posts: 265 Forumite
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    If it was the relay gives error 19 looking at the manual

    00 is mains voltage fault as you said reference voltage of 270 if about 40 v to high

    You say have a meter what is the measurement of AC on your home
  • ard123en
    ard123en Posts: 265 Forumite
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    “Grid Voltage Fault”
    The grid voltage has exceeded the permitted
    range according to local gird regulations.
    Following conditions might lead to this error:
     Grid voltage is out of the range rating.
     Sudden change to the grid.
     Grid impedance at the terminal of the
    inverter is too high.
    For safety consideration, the inverter will
    disconnect from the grid for a short time till
    the grid return to normal.
     Check the grid
    voltage.
    If this event occurs
    continuously and the
    inverter doesn’t work:
     Please contact your
    f
  • ard123en
    ard123en Posts: 265 Forumite
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    My gut feeling is that it can't sync with the main so shuts down.

    That's why ok with no DC as no production
  • Aia
    Aia Posts: 13 Forumite
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    edited 23 January 2018 at 2:12PM
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    Just a little update. My panels are not arranged in a simple way, and the installer actually added more after I complained there was plenty of space to add more on the side of my velux window (they messed up and said I could not get 4KW) . But I think there is 2 'strings' as there are 4 wires coming from the roof in to the inverter, ( they combine inside the inverter), this would go with my initial voltage readings which would indicate 7 and 8 panels (i have 15 in total at 260W each, which gives me a 3.9kW system)

    I disconnected the positive and negative DC from one string of solar panel, and the inverter once restared started to work fine

    removing the connected pair and reconnecting the other pair, and the fault light appeared once again.

    I reconnected the other pair again and its all working again, so I believe their is a fault with that side or something. Maybe a damaged wire. Annoyingly the inverter is not giving any fault codes

    My next step is to take some voltage reading once the weather improves. (the results I took were a little unsual and erractic becauase it was showery outside. And also try to look and see if any wires are damaged. Possibly caused by the pigeons?
  • Martyn1981
    Martyn1981 Posts: 14,764 Forumite
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    Aia wrote: »
    But I think there is 2 'strings' as there are 4 wires coming from the roof in to the inverter, ( they combine inside the inverter), this would go with my initial voltage readings which would indicate 7 and 8 panels (i have 15 in total at 260W each, which gives me a 3.9kW system)

    Slight digression, but if you do get a new inverter, make sure it's a dual MPPT inverter, otherwise the two strings will need to have the same voltage (same number of panels per string). If your inverter is a single MPPT, then it's probably been running as 2 x 7 panel strings wasting 1/15th of your generation.

    I tried searching Sonnen Macht and their 3.6kW inverter allows 2 inputs, but is single MPPT. But I've no idea if that's the inverter you have.
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW). Two A2A units for cleaner heating.

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
  • zeupater
    zeupater Posts: 5,355 Forumite
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    Hi

    The DC strings should both have DC isolators, therefore there should have been no reason to disconnect the strings, just independently isolate the strings (if possible ?single 4way rotary DC isolator?) ...

    Anyway, the OP needs to be very careful, we're talking potentially high DC voltages here, so don't want any accidents!

    I suppose that if an installer was tracing a fault, they'd be interested to discover if the problem is definitely with one of the strings, not one of the inverter circuits ..

    HTH
    Z
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    B)
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