SMA troubles

[jma]

Well, it has been awhile. My system had been working well till after the power outage caused by Ian, by the way, all the best to anyone affected by it.
Now I keep getting error codes 3401, 3402: DC overvoltage, overvoltage input A(SW) or B(SW). It's not generating any power so I called the installer about this and what I was told made no sense to me.
I was told this a common problem that will correct itself in the near future as the power grid stabilizes...their words, not mine. I asked if shutting the system down and powering it back up would help resolve the issue, they said it might, so yesterday I did that in the AM, the inverter displayed that code for about 40 minutes, then it produced power for the rest of the day.
At 7:43 AM today the error came back and no power is being produced.
I called the installer again and was told again to be patient, it will correct itself. I'm no expert but I don't buy this explanation. Any help on this matter is greatly appreciated, I want to find out as much as I can to decide what to do next. I'm going to to try to get in touch with SMA in the meantime, maybe they can shed some light o this....
Thank you in advance.SP110042022.JPG

[oregon_phil]

Looking back at the original thread, you didn't say how your system is configured. Do you only have two strings? What is brand and model number of your solar panels?

You have an SMA system that uses the SMA 2014 Rapid Shutdown box. This particular RapidShutdown box operated independently from the inverter. To turn off DC from the roof, you push the RED emergency stop button that is near your inverter. BUT YOU NEED A SPECIAL KEY TO RE ENABLE THE EMERGENCY STOP BUTTON. In other words, if you push the E stop button and don't have the key, your system will not allow DC from the roof to your inverter.

The nice thing about the SMA 2014 Rapidshutdown box is that full DC voltage comes down to the DC inverter terminals if the RED emergency stop button is not pushed. IF YOU HAVE THE ELECTRICAL ABILITY AND KNOWLEDGE OF WORKING AROUND HIGH VOLTAGE DC, you can measure the DC string voltage at the + and - terminals at the inverter. If you are not used to working around electricity, don't even try this. If you get the DC voltage reading, you can tell right away if the voltage is under 480 max DC voltage.

One other thing. I noticed in your log file that it says bridge strings determined. Given the design of the SMA 2014 rapidshutdown box, that means your two strings are paralleled right at the rapidshutdown box. Because of this, most likely, what ever faults Input A throws, Input B would also thro

[jma]

Hello Phil,
I'm attaching a couple of pics with the panel and inverter info. I assume it's two strings: the error codes mention A and B, does that make sense?
There's nothing listed on my Sunnyportal as far as strings are concerned. I do have the key to re-enable the emergency stop button.
Do you think it may help to do a rapid shutdowwn and then power it back on?

Thank you!

[oregon_phil]

Don't assume anything.

Please get the solar panel information. (sorry abou that. I didn't take the time to read everything in the first picture you sent. My apologies)

Do you have the as built drawings for your system?

SunnyPortal is OK but not useful for troubleshooting.

Can you access your inverter directly through your network? I know you have ethernet attached since data is being pushed to the cloud.

[oregon_phil]

Mission Solar MSE310SQ8T: Voc = 40.12

This is where it is really important to figure out how many strings you have and how many panels are in each string.

Assuming 12 panels is a string:

String voltage for 12 solar panels = 12 * 40.12 = 481.44 Vdc

SMA 7.7 -40 rated input range = 280 to 480 Vdc

12 panel Voc voltage 481.44 Vdc is over inverter DC input range max 480 Vdc.

[jma]

Nope, no drawings. I asked for them many times to no avail.
I can access the inverter via cell phone or tablet, no ethernet cable attached.
Some good news: I found a local installer, in my back yard literally, who will be here tomorrow or Thursday to help sort this out. We'll see how it goes.
Let me know what I should be looking for when I connect to the inverter later today.
Thank you!

[oregon_phil]

You must have a wifi connection. From your tablet, are you accessing SunnyPortal or the SMA inverter directly?

Are you network literate? Can you get to your router to see the IP address?

BTW, my installer had to submit drawings to the county for permitting. Perhaps your installer did the same.

[oregon_phil]

Have your new installer take pictures of the inside of the connection box (lower black box). In particular, how many wires come out of the conduit from the roof? Is there a splice in the wire from the roof that goes to both Inputs A and B?

Also, measure the DC voltage between A+ and A -, B+ and B-, and C+ and C-.

While you're at it, you might as well measure AC voltage since the box is open.

[jma]

I access SunnyPortal via wifi with a PC, cell or tablet.
I can access the inverter directly, just did. look at attached image, it may be of some help?
On the advice of the local installer I reset the inverter after using the rapid shutdown, nothing to lose at this point....
I t did reboot, no errors, however it's only generating ~1500 w, when it should be generating over 6000, full sun about 1.00PM. Don't know what givesSMA settings.JPG

[jma]

Forgot, yes I will take pics when the installer comes in.

[oregon_phil]

When you access the inverter directly, are you logged in as user or installer?

On lower left corner of the home screen, what version of firmware are you using?

When you select instantaneous values, what categories are you able to select?

[jma]

I am amazed at your knowledge, here it goes, taken a few seconds ago:

[oregon_phil]

Two lines of thought:

1) Rapid Shutdown device needs to be tested. Search RSS-US-IA-xx-15.pdf and download the manual. The Rapid shutdown manual is too large to load via uploading attachments. Page 34 of the RSS manual shows how to test proper functionality. If you press the Red E stop button, red LED flashes briefly, then green LED glows constantly, then Rapid shutdown most likely works properly. Perform this test and report your findings.

2) The instantaneous values file that you provided show ZERO power for String A and B and 1720 watts on String C (at 227.24 VDC and 7.572 amps). It also says inverter function is OK.

The Rapid shutdown device is powered by String A, and since String C is getting power to the inverter, this implies String A is getting power to the rapid shutdown device but power is not getting to the inverter or the inverter has turned off Input A and B.

Please reread what I said in post #6 of this thread because knowing string length is critical.

Things that need to be figured out.

A) String C length: Maybe somebody can help me out here. Panel Vmp is 33.17. Input C was running midday at 227.24 Vdc/7.572amps. Palm Coast Florida weather today says sunny all day. I was assuming 3 strings of 8 panels, but is there anyway to make a guess at string C length from Vmp and actual string C voltage? If string C length is an odd number, then there is no way to properly parallel strings A and B at the rapid shutdown device since OP has 24 panels.

B) SMA suggests using a polaris block inside the inverter to parallel inputs A and B. I know from experience that improperly installed polaris blocks on a high voltage circuit can become high resistance and will eventually fail. The new installer should check these blocks for sure. Since you've already had the 4301 arc fault failure from almost day 1, I strongly suspect these are an issue; especially if any moisture has penetrated the inverter connections box (lower black box).

[jma]

I tested the rapid shutdown, it behaved just as you described.
You were right about the weather, not a cloud in the sky, ideal conditions and it was such a disappointment to look at the wattage being generated.
The new installer appears to be very eager to sort this out, hope tomorrow brings some good news. Till then.

[oregon_phil]

[QUOTE=Have your new installer take pictures of the inside of the connection box (lower black box). In particular, how many wires come out of the conduit from the roof? Is there a splice in the wire from the roof that goes to both Inputs A and B?

Also, measure the DC voltage between A+ and A -, B+ and B-, and C+ and C-.

While you're at it, you might as well measure AC voltage since the box is open.
[/QUOTE]

When you have your installer measure DC voltage above, have them turn the AC disconnect off. That way you will be measuring string open voltage. At least voltage of string A and B paralleled and string c. This way we can determine the number of panels in the strings.

When you turn the system back on, go into the log file and take a picture of the events happening during boot up.