Great and inexpensive monitoring system and a problem to solve.

[oregon_phil]

Can you talk the integrator into gaining full installer access? You are smart enough not to change parameters that will harm your system and your installer should know that by now since they have been working with you. That amount of data that can be downloaded off of inverters is mind boggling.

I have full installer access on my system and I bet most people on this forum have installer access. I'm just guessing. Most people on this forum are very knowledgeable.

[DanS26]

Although the monitoring I installed measures Voltage, I cant download that data yet, it is a feature planned for the Future. I will check it manually on the next event though,

But the Integrator has access to the full inverter data monitoring, so that will be his job if they agree the problem is real and requires investigation (again, I have not forwarded my new dat yet...)

Just looking at the production graphs it appears the fluctuations start and end at the same production levels.......to me that points to voltage.

[scrambler]

Just looking at the production graphs it appears the fluctuations start and end at the same production levels.......to me that points to voltage.

These are just tow examples, I have had several others where it is not the case.
And the inverter is not throwing an under/over voltage error

[Ampster]

........ the inverter is not throwing an under/over voltage error

The voltage could be okay but the frequency may have increased enough to trigger some curtailment. Do you have a way to check both values? If you look at the 1741 spec it refers to frequency and, if I am correct, a certain amount of frequency increase will trigger the inverter to curtail output. I am guessing that we can rule out low voltage and/or lower frequency since those do not typically result in curtailment. That guess is just an assumption and until it can be checked is just a guess.
The observation is that output is being curtailed, which you have documented. The hypothesis or issue to be resolved is what is triggering that curtailment?

[scrambler]

The voltage could be okay but the frequency may have increased enough to trigger some curtailment. Do you have a way to check both values? If you look at the 1741 spec it refers to frequency and, if I am correct, a certain amount of frequency increase will trigger the inverter to curtail output. I am guessing that we can rule out low voltage and/or lower frequency since those do not typically result in curtailment. That guess is just an assumption and until it can be checked is just a guess.
The observation is that output is being curtailed, which you have documented. The hypothesis or issue to be resolved is what is triggering that curtailment?

The inverter also has error codes for frequency out of range (up or down)

[DanS26]

Thermal or wind movement in wiring causing intermittent or high resistance connections.

[Ampster]

The inverter also has error codes for frequency out of range (up or down)

Okay, is the definition of "out of range" the same frequency as the frequency which determines when curtailment begins?

[scrambler]

Okay, is the definition of "out of range" the same frequency as the frequency which determines when curtailment begins?

I honestly don't know, so I will add that to my list of things to find out.
I am going to first let them come up with some possible explanations though

[oregon_phil]

Scrambler, I tried to piece together some of your data in the following .pdf.

I think it is reasonable to rule out the following potential causes:

8: Bad utility connection. Doesn't happen to Enphase
7. Bad Tigo: Happens on both MPPT channels. What is the probability of one bad TIGO on each string? low
6. Bad AC connection: Your installer checked this right?
4. Bad solar panel: Happens on both MPPT channels. What is the probability of one bad solar panel on each channel and that you left the two bad solar panels, one on each Darfon MPPT channel. Low

Can the following explain your problem?

5) DC connection: Possible. Lets say you do have a bad connection and you have several hundred volts across it. In my case, the Arc fault detection circuit picked up the noise from the bad connection and faulted the inverter. And generally the connection would keep getting worse and worse and worse until?

3) Bad data reporting from inverter: Maybe the inverter is working correctly except for the reporting function. Bad sensors/detectors? From the fried battery board incident? It's probably not just bad reporting because the sensors are the same.

2) Firmware not working properly: Possible. This can be proved by new firmware or new inverter.

1) bad inverter: maybe a sensor did get damaged during the battery board incident and is sensitive to thermals, etc. Other explanations?

[scrambler]

To Oregon_phil. I also have Arc fault detection; The DC production is reported both by Tigo and Darfon and the new monitoring reports the Darfon AC out and they all track;

*** At this point I will put this one to rest until I have forwarded all my findings to them, and they have had a chance to review the inverter internal data, and speak with Darfon. ***

Thanks all!