Sunny boy / island active power limitation

[Ai4px]

I've got a pair of sunny islands with AFRAENA on, so when separated from the grid, I should have freuqncy shift power control. There is no RS485 comms between the SI and SB.... Sunny island is in island 60hz mode and wired behind the Sunny islands. I've watched the power carefully on an external power meter with a handful of CTs and when in AC coupled frequency shift mode, I see the power produced by sunny boy chasing the power used in the house, kinda neat to see.

Yesterday we had some issues with the grid and today also again.... both days after a few blips of the grid, my sunny boy stopped producing power. At this moment we are coupled to the grid and sunny boy is showing "active power limitation at the moment". I went thru the "installation assistant" and turned off all power control but we still have active power limitation. I can't understand why.

I have run this way (frequency control of power, no rs485) for a couple of years without issue. ANyone have any ideas?

 

[Hedges]

"Active Power Limitation" isn't something I've dealt with. I would like that for export limit.

I did cause my phase 2 slaves #1 and #3 to shut off. I had introduced a bonded fault in the grid side of Sunny Island, which would have caused one phase to go to zero for about 8ms then recover when breaker opened. The Sunny Islands thought their internal relay has stuck closed, and halted. This caused phase loss to loads (which was only Sunny Boys that day.) I'm considering trying the phase failure shutdown setting (which mentions 3-phase, hope it works for split phase.)

I also saw one Sunny Boy give error "MSD-Idif", then recover. Apparently two circuits inside had different readings of grid connection. Only thing I can think of was VFD powering 2 HP pool pump, connected to grid side rather than island side that day.

"AFRAENA" may be a red herring. I think that is just having frequency drop below nominal for a while so mechanical clocks end up back on time after frequency shift sped them up.

I think Active Power Limitation is something done through Data Manager, possibly involving web connection.

Configuring Limitation of Active Power Feed-In

manuals.sma.de

Probably this means the local utility is receiving excess power from distributed generators like yours.
If you disabled that (if you can), would think it would start producing.
Try turning on loads at the house, see if it at least produces what you consume.

 

[MurphyGuy]

Take this with a grain of salt because I'd have to check it..

I seem to remember that whenever my Sunny Islands were throttling the array by raising the grid frequency above 61hz, the active power limitation showed up on my Sunny Boy's web interface.
I'm not entirely sure, but I know that my screen usually says "The active power limitation is deactivated" almost all the time.. and we're totally grid tied almost all the time.. and the only time I can remember it saying it was active was when we were off grid.

I've seen it do this a couple of times, never gave it much thought. I suggest you go into the instant values tab and check the grid frequency to see what's going on.

You could also pull out the old reliable Microsoft Window's fix and just reboot everything.

 

[Ai4px]

The problem fixed itself after sunny boy got a good night sleep. The next morning it was fine, active power limitation was gone.

I've since replaced my HVAC 5 ton heatpump with a 3.5ton ducted minisplit. 100% of my power problems have gone away. The heat pump compressor didn't glitch the inverters every time it started but probably every 10th time.... I can only speculate that depending where the 60hz waveform was at the moment when the compressor started, the measured power factor might have been affected. Sometimes the start inrush was so severe that it would make sunny island go off grid for 5 minutes.... sometimes the upstream "always on grid" solar edge inverter would stop making power. Since the minisplit install I've had no issues.

Here's the heatpump starting (spike is much worse, this is a 1 second average)


And here is the minisplit starting


I went with the 3.5ton minisplit for two reasons.... start surge and tons.... the 5 ton was a two stage unit that ran at 3tons most of the time. Matter of fact I can only think of two occasions when it ever ran at the high setting. It would typically run 6-7minutes and shut off. THe minisplit can ramp up to the same capacity but instead spends a lot of it's time at 1200watts. This will make load management a lot easier as when I'm offgrid I would have had to shed loads to provide the overhead for the heat pump to start...now I don't have to worry about that.

I know this probably sounds like it's off topic from my original post but I believe the start surge from the heat pump was the source of my power limiting and power factor problems.

 

[Ai4px]

Just for grins.... this is what the minisplit looked like last night running. The house is well insulated and it is 44F outside... the minisplit finally came on a 415am. Beats the heck out of start stop start stop start (glitch inverters) stop start stop.