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- เผยแพร่เมื่อ 22 มี.ค. 2021
- The first site has low specific yields (that is kWh per kWp per year) and was taking time to get going on a winter morning, a classic sign of an insulation resistance / isolation / Riso fault. I think the low yields were down to a blown fuse in the inverter which I replaced, and marked the date so that anyone else visiting knows that it's had a problem before. The smashed module was located under a tree which is a recipe for trouble, I disconnected it and shortened that string by one module. Not ideal but not the end of the world. At some point when someone is in the area for another reason it'll get replaced. Not worth a visit just to replace a single module.
The second system had three inverters. One with classic Riso fault symptoms of being slow to get going in the morning when it's damp, unfortunately I got there late afternoon so it was generating when I was there but I found a smashed module (I'm guessing by a football) and disconnected it. The other inverter issue wasn't displaying the normal morning issues and was cutting out at various points during the day so didn't initially point to a Riso fault. But that's what it was.
There is another (more scientific!) way to guess where the fault might be in a string is instead of going with your gut feelings. You can measure the voltage from either side of the string to ground. If it's grounded in the middle you'll get something like +300 and -300V. If it's grounded 3/4 of the way along it might be 450/150V etc. Or you can just go "I bet it's there..." and hope for the best.
Both these systems are quite old hence the low voltages. We tend to be designing 2-300V higher now, depending on roof and string layouts.
Neither of these sites are managed by me, and whilst the person that does manage them is rather more efficient than me you can never guarantee that they'll remember to pass on site notes.
I would love to try a cable tracer but they're expensive and I can manage without. I don't want to kill my network cable tracer trying out whether it could work! But if anyone's got a spare one they don't mind me experimenting with...
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Thank you for this clear and concise Solar repair documentation. Keep at it!
There are tons of videos about new and beautiful installations. It is very interesting to see the reality of the corroded messes that these become in a few years :) I would love to see some videos about common pitfalls and typical mistakes in solar installation, and the resulting messes...
I would say that cable joints (MC4 connectors) not made properly and connectors not cable tied up to the back of the panels are probably the most common installation issues. When you get connectors sat on wet roofs they just get sodden, even if they are properly tightened IP68 rated. Not a very exciting video!
However.
The single most common failure (of the solar bits as opposed to comms) across our portfolio is SolarEdge optimisers. I look after about 5MW, we work closely with another portfolio that's a little smaller and a bit older (where these videos/pictures were taken). SolarEdge makes up about 1/3rd the capacity and 3/4 the faults. Per 100kW I would guess we get an optimiser failure a year. That sort of number. We've got about ten broken at the moment and it's not worth fixing if I'm not already going there for some other reason.
How difficult is it to get a free replacement from SolarEdge for the broken optimizers? Do they bring down the whole string when they fail? Did you ever take one apart to look inside what failed?
@@tamask001 It's pretty easy to get replacements, and you can get a bit of money back for changing them if you jump through the hoops.
They thankfully do not take down the whole string.
I've taken a couple apart, and keep them around for harvesting parts to make adapter cables and odd job tools with. The entire thing is potted in rubbery goop so it's pretty tricky to seen anything. You can peel it off the PCB but I've not seen any obvious signs of the magic smoke escaping. They seem to fail short circuit on the input side.
One of the really great things about the SolarEdge system (up to a point) is the online monitoring. It gives you an overview of what every panel or pair of panels is producing. Assuming you've set up the system correctly at the start it makes locating faults very easy. Unless they're in the middle of a roof that you can't get to!
In principal you're supposed to be able to change a load of SolarEdge settings from their portal but that option doesn't seem available to me, it's something I need to take up with their support team but there are higher priorities!
The newer SolarEdge inverters have their "SetApp" phone app which works reasonably well but appears to have a range of less than a meter so no walking round the roof whilst trying to check on the parameters.
The older ones have an arcane interface with a single pushbutton and it's almost always quicker to remove the cover (which is very naughty if you haven't isolated it etc etc) to find there are four buttons inside and a menu system that actually works. Quite why they can't follow ABB's (or whatever they're called now) lead and just have the buttons easily accessible I don't know.
The 50kW SMA Core1 inverters have a built in webserver so accessing their settings and diagnostics remotely is really easy. The 25kW and below do not, so unless you've set up a local VPN at the inverter end you can't access much beyond the basics which you can get through SunnyPortal.
The flip side of that ease of remote access to the Core1 is there is no local interface. If your installation team doesn't have a laptop with them they can't set any of the grid protection settings and that's a problem in initial commissioning. In theory there's a phone app but I've never been able to get it to connect! It's the sort of thing on the rare occasions I have some free time on site I give it a go until I get bored and fish my laptop out.
Great job in troubleshooting and thank you for sharing your work you are definitely a skilled person
Thanks for watching and the kind comment, you may be being overly generous :D
There's a lot down to luck and intuition. You just have to make the conditions right for a lucky find!
Hello from France this is the massive issue in photovoltaïque system. I am in charge of more 200 installations, most of them reaches 100kW. When the fault isn’t in the line of panels, when it’s in the câble whom is linked between the inverter and the panels we still haven’t found the perfect tool to find the location of the fault.
Sadly neither have I.
I've seen quite a few installs with damp in the cables or entire strings that are a bit damp. Sometimes the array itself is fine but the cables from the array to the inverter are the fault.
Break it down in to sections, each elements tests out fine. Combine it all together and it has low insulation resistance. I just put it down to damp British weather so I'm glad to hear it happens in France too :)
Hi mate, good videos. We have an issue with a job where you get a small shock when touching the aluminium flashings (connected to the aluminium panels) and the scaffolding only when its raining heavily. It is an inline system and the tiles have yet to be finished. The cables have been checked and seem fine. Could it be an issue with the connections sitting in water? Be grateful to hear your opinion. Alex
Hi what is the cable tracker called was looking on line and can’t find
The cable tracker?
I was using the Seaward Solar PV150 as the string tester, and my clamp meter (RS 156B) to measure string currents.
If you disconnect one string and have all the rest generating, you can wander round testing string currents to identify which string isn't generating.
On other jobs I've put a bit of tape on the top of the panel to make it more obvious.
Hello I'm having trouble at a site with an inverter saying Fault "Imbalance Bus Load" I am pretty new to the field, any advice?
Hmm, I'd start by looking up the manual from that manufacturer. Not one I'd come across before, but a lot of weird inverter error codes end up needing a replacement sadly.
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Plz help me