"Grid voltage fault" after power cut / generator

[dignut]

Hi there!
We've got a domestic PV array with a Sunny Boy 1700 inverter that's worked faultlessly for a decade.
Last week there was a power cut in our locality, and excitingly, a big lorry with a generator turned up and was connected to the little substation that's in our road just a few doors away.
Our solar system took a dislike to this, and shut off, quoting a "grid voltage fault; error code 1401". Looking this up on the SMA site, the closest seems to be "401":

Grid fault / Island grid (401)

The inverter is no longer in grid parallel operation and has stopped feed-in operation for safety reasons.
Corrective measures:

• Check the grid connection for significant, short-term frequency fluctuations.

I've also seen reference to a "stand-alone grid" with respect to this code. I assume the generator output wasn't to the inverter's taste in some way with the voltage/frequency.

Anyway, the generator's been gone a couple of days though, and I assume we're back on the normal grid, but the fault still remains. I have a Sunny Webbox, and the red light is coming on each morning, and no output. I phoned National Grid earlier, and they are sending out a technician! I hope this isn't going to be a colossal waste of their time.

Any thoughts? Is it as simple as nipping up to the loft and turning the inverter off and on again at the master switch? Or can I reset via the Sunny Webbox interface? Or do we need to get an electrician in? I obviously don't want to do anything that could cause damage.

Thanks in advance for any information or advice!

 

[dignut]

EMBARRASSING UPDATE:
The National Grid guys have just been. That was amazing service: I only made the phone call a couple of hours ago. After testing the voltage coming to the house (all normal) they noticed that the trip switch on the fuse board for the inverter was up! It must have tripped during the initial power cut or reconnection. A quick flick of that switch, and the system was working again.
The guys were very gracious and said that I'd saved them from going to other, nastier jobs!
I was tempted to delete this thread, but shall leave it in case anyone else has a similar situation. Before assuming there's a Big Problem, check the simple stuff! ?

 

[Hedges]

That may have shown up as voltage or frequency on Sunny Boy display (varies by model.) Mine will indicated tripped at 64 Hz, now 60 Hz, etc.
Sunny Web Box should let you see instantaneous voltage and frequency, which would have reflected disconnected voltage.

By the way, Web Box has vulnerabilities if connected to the internet.

SMA WebBox vulnerabilities

Got SMA WebBox connected. It is able to see the SB5000 and SI-6048 I'm using, display and presumably alter their parameters. My unit has RS-485 for communication with inverters and Ethernet for PC/network (other models have Bluetooth but lack legacy networks.) Reading that it supports FTP with...

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