Grid noise forcibly shuts down my two systems

[solarintexas]

Phil, while I read your last reply, I noticed that my inverters were starting up at 12:07 pm for two days in a row. Then, surprisingly, the day after, they reverted back to normal and have now been operating normally for two, three days.
vexing, really. I assume that whatever firmware controls them has some sort of internal logic to reset itself after an incident, I did not get a chance to read the status LED when they were not functioning properly (I was sick then, didn’t want to climb on my slippery metal roof), but I am 100% certain, that there is no negative interaction between my SMA and the micros.
Anyway, since the micros are back in business, I will let them be for now and watch how they keep performing. I do not know whether a possibly newer firmware would solve my specific problem. If they kept malfunctioning, I would pursue a warranty claim with Enphase. As things are, I will wait and see.
the problem is that Enphase has not published any specific protocol about how their inverters will perform during certain situations. What are the scenarios that could trigger such behavior? For how long will the inverter be locked out during, say, repeated grid failure incidents, etc? There is a huge black box that the manual and their technical literature does not address.

Anyway, mainly just glad that my micros are making power again. Getting ready for 100+ deg. F weather here in the next few days.

[solarintexas]

Haha. Never mind. Another grid “event” occured this morning, micros are out again, and string inverter is fine, as always. I suppose I need to get my magnetic boots on and climb on the roof to investigate the status LEDs. I will report my findings.

[solarintexas]

The problem has been solved, and I wanted to post an update to let you know what was the culprit.
Turns out there was nothing wrong with the equipment. My grid voltage had crept up over time, reaching at times 256 volts. My Sunny Boy was more accepting of the high voltage than the IQ7+ inverters, but when it, too, eventually started to cut out for longer periods, I knew something was wrong.
The utility people came out at first, wanting to tell me that 127V on one leg was “perfect”. Naturally, that was a bunch of nonsense. I made a call to higher management, and they promptly instructed the crew to adjust it. Turns out they somewhere in the system “forgot” a capacitor bank that they removed. They ultimately admitted that this was an oversight and their fault and even thanked me for “discovering” it. The removal of that bank permanently brought down the voltage to below 250V/125V. I have that manager on speed dial if it ever causes problems again. I suggested a tap adjustment on my transformer pole, but as of now that doesn’t seem to be necessary.
Goes to show that you have to do your own investigation and insist when professionals shrug your concerns off at first. Altogether, I have to say that the utility came around and clearly showed their willingness to help. I have perfect production now. No more dropping out of any of my inverters.
Thanks all for chiming in previously with your ideas and support! I much appreciate the helpful attitude of forum members here.

[bcroe]

Thanks for the report on the problem and the solution. Seems this
is not such an unusual thing. Here the guilty seem to downplay it
as a "temporary" thing, just wait and it will go away. I see it as the
value of my system going right down the toilet for no good reason.
Renewable energy cannot just be made up later, it is gone.
Bruce Roe

[Sunking]

My grid voltage had crept up over time, reaching at times 256 volts. My Sunny Boy was more accepting of the high voltage than the IQ7+ inverters, but when it, too, The utility people came out at first, wanting to tell me that 127V on one leg was “perfect”. Naturally, that was a bunch of nonsense.

]Hogwash. Utility tolerance is +/- 10%. 254/127 is as good as it gets. It is your crappy equipment.

[solarintexas]

That 10% tolerance number is on the very outside of acceptable. Not sure what your source is that this is good or desirable. Such an excessive range can cause all sorts of problems with household devices.
ANSI C84.1. Is what most utilities aspire to, preferably Range 1. That is also what my utility uses as a target.
And thank you very much for the kind words.