Sol-ark 15K over/under frequency faults

[Mercracing]

My system is a Sol-ark 15K with 8.2 KW of Sunpower panels on a ground mount (no batteries or generator at this time). The system was installed by a local solar/electrical company. While I am pretty familiar with what things are supposed to do and how they function I am definitely not an expert (not a build my own system skill level guy). We keep having F47 Over Frequency (x7 on the screen that I can see) and F48 Under frequency (x1 that I can see) errors that cause the inverter to disconnect from the grid and restart itself. The outage only lasts about 60 seconds, but it causes all of the clocks to shut down and my wife is getting irritated. I have spoken to Sol-ark and they are blaming the power company (Evergy) and the power company is blaming Sol-ark. Sol-ark had me widen the frequency range to 55-65 hertz and turn on a some other feature (I am forgetting the name) that is supposed to help this issue. I live in a rural area about 20 minutes from a town of about 5000 people so we are in the country a little, but not the third world. I unfortunately do not have any logging equipment to try to catch the issue (Powerview only reads in 5 minute intervals). Sol-ark's position is that the grid needs to get it together or I need batteries (which will make everything all better). I have a call in to the installing company requesting assistance but my system was their first Sol-ark and I am not super confident in how much help they will be. I would appreciate any advice or guidance the forum has to offer.

Thanks,
Ryan

 

[Mercracing]

Sorry, forget to add the following. The faults happen at all sorts of random times and conditions.

 

[Hedges]

While I haven't used SolArk, I would guess transients are confusing it. Getting both over & under frequency faults with 55 Hz to 65 Hz range is unlikely.
Confirm what parameter is set to that frequency. That would not be allowable for UL-1741 backfeed, so maybe it is only an off-grid setting.

It would be useful to at least use a DMM and read voltage and frequency.
Better to also look at waveform with a scope. Maybe installer can try that.

Since you spoke to SolArk, I presume it is already updated to latest firmware? Firmware could do a better or worse job of reading frequency despite transients.

Perhaps you have bad connections, which are arcing and causing noise. With an extension cord from a different circuit, you could use DMM to check voltage from L1 of SolArk to L1 of an outlet, then L2 to L2.

Do you plan to add batteries? Can installer hook up a loaner to check? 48V of lead-acid battery should make a nice buffer for fluctuations, maybe 4x used car batteries from the junkyard.

 

[Mercracing]

Thank you for the response. I have not tried using a meter yet, though I have a Kill-A-Watt plugged in where I can see it from the kitchen table. I have never seen it move more than from 60.0 to 59.9 or 60.1. That seems to apply to when the inverter has solar to operate or at night when the grid is passing through. The frequency range was set in the grid section of the menu (as it was explained to me the range tolerance the inverter would handle from the grid).

 

[Hedges]

So the actual frequency is 60 Hz.
I'm guessing different sampling/filtering by SolArk. Or, bad connections lets it see glitches.
Is SolArk backfeeding? Or just supplementing downstream loads?

Can you test by programming for lower output, maybe 1kW limit? That would see if less current from SolArk makes it less likely to be upset.

Or is this at night, when power is drawn by the grid?

Try shutting off AC and DC power, confirm with meter wires are dead, check that wires are snug.
After first tightening a connection, wires tend to settle especially if wiggled and need re-tightening. That would make hot connections, maybe also arcing. IR thermometer or camera might see hot spot.

There are parameters for how long out of frequency range is tolerated. But 5 Hz off, would disconnect immediately. Ride-through of 5 minutes is for 1 Hz or less off.

 

[Solar Guppy]

Likely it is the power company and its been happening before you installed the inverter, the difference now is you have an inverter without a battery that likely switch's to backup using the solar ( but no battery ) and sometimes the home loads are to great for solar only. So in the past, a second or two blip went unnoticed, but with the inverter going into bypass it is more apparent with the 60 second restart.

Since this is a turn-key installation, time to get the installer involved and have them do the legwork to track down the cause. Also the inverter should be sending data to the cloud so more information should be available to what the inverter sees happening, something the installer should have setup.

 

[Mercracing]

I am waiting for a call back from the installer currently. I am not/have not been super impressed with them so far, so I'm not overly optimistic. We have been having this issue occur two to three times a week (only when the solar is functioning) under pretty much any range of conditions. For example, the fault last night was at 8 pm with less than 200 watts coming in from the panels and pulling about 1900 watts from the grid. There has never been a fault occur when the inverter is passing the power through from the grid without any solar, with the absence of a battery the Sol-ark shuts off once the sun is down fully.

 

[Oldphile]

I experienced an F47 fault after a power failure. The Sol-Ark disconnected from the grid and did not reconnect. A call to Sol-Ark resulted in a firmware update and the fault never reoccurred. This was shortly after turning on PV when first installed. It's been 5 months now without a fault.

 

[LydMekk]

I recommend that you get enough batteries for your needs.
Running it without any batteries will create issues.
Esp. in periods without grid or during loadshedding.