diy solar

diy solar

Sunny Boy frequency-shift regulation of power output - which models work per spec?

Mechanical clock in an electronic stove?
Or is that an electronic clock that uses line frequency for timing?
Could be a poorly trimmed crystal based clock.

... and transfer one array with about half the solar back to the grid, in response to the battery voltage and the SI frequency.

Switching a grid-tie inverter between Sunny Island and grid?
Sounds like a risk to connect with reversed phase. Unless the switching has 5 second "off" time as recommended by SMA.
 
Mechanical clock in an electronic stove?
Or is that an electronic clock that uses line frequency for timing?
Could be a poorly trimmed crystal based clock.
I haven't really looked into what it is, brand new Frigidaire induction range. A 10yr old Sony . It could be our imagination also.
Switching a grid-tie inverter between Sunny Island and grid?
Sounds like a risk to connect with reversed phase. Unless the switching has 5 second "off" time as recommended by SMA.
Your point is valid, I would not use a single double pole double throw relay to switch the microinverters. Maybe it could be fast enough to reconnect, likely out of phase, before the solar inverter had tripped off. I use a pair of mechanically interlocked contactors, and there is some control delay between the switch between grid and off-grid (SI AC1). The Enphase spec sheet for the old m190/m210 says .16 sec

https://photos.app.goo.gl/UcDfekbC1J3qAJ6J9 The transfer switch for the GT solar array, when being controlled by node red & RPi, waits two seconds. Before that RPi control was set up, the pair of timers were used and are set to wait several minutes.

These little din rail timers have an internal battery for their clock, maybe that would work for your loads controls (timer not affected by the AC frequency).
 
Good you've got a delay!
I was wondering why it hadn't blown up already.

Here's the timer I got. (same model from eBay for less, and in stock)
Although it has 120VAC input, I think that is just for relay coil and timer is powered continuously by CR2032 coin cell.
I will use the relay for pilot duty, closing a heavier relay for loads like water heater and dryer element.


 
Yes, off-grid mode of Sunny Boy 10000TL-US works over the frequency range my SI delivers.

Older document SB-OffGrid-TI-eng-UUS121312.pdf says

"Backup systems with SI 4548-US-10, SI 5048U and SI 6048-US-10
In the event of a power distribution grid failure, the off-grid inverter sets the "Default" parameter of the PV
inverter to "OFF_Grid". Thus, if a grid failure occurs, the off-grid inverter is able to regulate the PV inverters via
Frequency Shift Power Control (FSPC). When the grid returns, the off-grid inverter sets the "Default" parameter
of the PV inverter back to "UL1741"."

"The setting of the "Default" parameter to "OFF_Grid" automatically sets the PV inverter parameters to the values
listed in the following table:"

"Fac-delta‒ lower range in which the Sunny Boy is active relative to f0 Hz ‒3.0 (starting from the base frequency f0)
Fac-max+ upper range in which the Sunny Boy is active relative to f0 Hz +3.0 (starting from the base frequency f0)"

I suspect "Default" parameter isn't literally changed, and the -3.0 Hz setting doesn't happen.
Sunny Boy 5000US does note that it is in backup mode and mostly works, but I suspect not everything gets set right.

I might have to Turn off 250.11 AfraEna, but I was planning things like dumb mechanical timers to shut off loads at peak rate times.
I have used Harbor Freight timers but the relays fail. I got some others which I'll switch power contactors with.

"Creep forward", you say. You don't have the excess power I do. Off-grid, it spends a lot of time at 62 Hz. That's 3.3% fast several hours per day, would slip my timers by an hour in no time, and mess up my time of use dodge.

If you want something done right ...

Got tired of waiting for SMA to reply, possibly with a workaround.
Since SB 5000US seems to work in backup mode when frequency increases (responding by ramping down power from 100% at 61 Hz to 0% at 62 Hz), but disconnects at 59 Hz, I considered changing low frequency disconnect setting.

In off-grid mode, it is supposed to work at 60 Hz +/- 3 Hz. My operation of 10000TL-US worked in the range it saw, and disconnected somewhere at or above 63 Hz (saw 64.5 Hz on my meter, maybe it did trigger at > 63 Hz.)

In UL-1741 mode, it is supposed to work at 60 Hz +0.49 -0.69 Hz.

Rule 21 (not considering frequency-watts) requires inverters to ride through as low as 57 Hz and as high as 62 Hz, for 5 minutes, then disconnect if still out of spec. Near-nominal 58.5 Hz to 60.5 Hz, it is to operate continuously.

For the issue I found with 10000TL-US (didn't ramp down power in response to frequency), SMA gave me the workaround of putting in in off-grid mode. Because it is behind Sunny Island, which takes care of UL-1741 and anti-islanding. My concern with that is, if relays in Sunny Island weld shut, Sunny Boy is hardwired to the grid and doesn't obey UL-1741.

So rather than the off-grid workaround, I want to keep using grid-backup, which Sunny Island controls by RS-485 signaling. Widening its on-grid settings to 60 Hz +0.49 - 1.10 Hz, it is within the limits of the new Rule 21.

That seems to fix the problem. I think Sunny Boy firmware, when it gets "Off grid!" message over RS-485, sets frequency range to 60 Hz +3 / -1 Hz. (or possibly leaves -0.69 Hz.) "-1 Hz" would be the range Sunny Island uses, but there must be margin between what Sunny Island drives and what Sunny Boy accepts.

DIY all the way, baby!
 
I used to think SMA were the Gods of inverters.
They were early and delivered quality grid-tie PV inverters.
They make fantastic off-grid power, integrating PV, generators, lead-acid batteries for a home or a village.

Grid-backup is supposed to switch between on-grid mode and off-grid mode.
Documentation explains that when grid returns, Sunny Island monitors the grid for 5 minutes (UL-1741 requirement), then synchronizes and seamlessly connects. But to ensure Sunny Boys don't deliver excessive power while synchronizing (e.g. if battery full and no demand from loads), it first raises frequency above the disconnect limit so Sunny Boys shut off. Then it lowers frequency to match grid or generator.

With 10000TL-US configured for off-grid, I observed it do exactly that.

With 5000US, it behaves a bit differently.
Frequency was hovering around 61.9 Hz (so only 10% of available PV delivered) because batteries were near full.
When I closed switch to grid, Sunny Island almost instantly signaled "On grid!", not waiting 5 minutes to qualify the grid.
Sunny Boy responded by tripping off-line due to frequency error (61.9 Hz is out of range for on grid mode.)
With no AC power coming in, Sunny Island dropped to 59 Hz. When Sunny Boy had previous 60 Hz -0.69Hz limit, that was out of range and kept it off. Now with 60 Hz -1.10 Hz limit, it is within range, so Sunny Boy starts monitoring grid for 5 minutes.
I though Sunny Boy might come back on line before Sunny Island reconnected to grid, but Sunny Island seems to connect sooner.

I never observed Sunny Island increase frequency to 65 Hz to knock Sunny Boys offline.
It may only do that if it has power coming in. I think it should do that even if it is delivering power to loads. It can't know if there are Sunny Boys delivering power but loads exceed production at that instant. It only knows net power. If a load turned off, excess power might suddenly be on the island grid.

So far so good, but I wish all the hardware performed as described. The concept sounded good. It doesn't look to me like equipment and firmware has been verified against all requirements.
 
This is a situation I had not given much though in my system.

I have not been running off grid with enough sun to top out my battery bank. The only time I saw mine do the frequency shift was when I had the charge current set low and it kept shifting the frequency to limit the charge power to the desired limit. I will have to see if I can look up how it handles grid reconnect once the batteries are all full. I assume it would have to do something similar. If it is frequency shifted up to 61.5 Hz to curtail the inverters, the current could very well climb a chunk when it drops back to 60 Hz to sync up with the grid. In the case of my XW-Pro, the reconnect time is very quick. But it then waits 5 minutes before the XW-Pro itself can export power, BUT... My Enphase micros may not even know they were ever off grid and could immediately start exporting as soon as the transfer relay in the XW closes. I noticed the very short delay a few times on other tests. I would close my breaker to the main panel, and in less than 1 minute, I would hear the transfer relay close, and the inverter status would be "Pass Through" "Qualifying".

My assumption would be that if it was in a curtail power mode with frequency shift happening, I would expect the Enphase micros would trip from a "grid instability" when it drops the frequency back to 60 Hz and shifts the phase to match up with the grid. That should start a new 5 minute connect count down for them as well. The XW starts a 300 second (5 minutes) count down on the display when the transfer relay closes. But at that time, the output loads (and therefore my Enphase inverters) are connected to the grid.

My XW-Pro and Enphase micros are all set to CA Rule 21 grid profile. They "SHOULD" follow the ride through and curtailment rules. But that is not something easy to test without forcing the system off grid.

I have not dealt with SMA, but I have worked on a bit of other German built tech gear, and every time we call their tech support with an issue, they start off with we must be doing something wrong. Their equipment and firmware always works perfectly, it has to be us screwing it up. Just like when BMW didn't offer a tilt steering wheel in the M3. "The steering wheel is in the right place!!"
 
If your XW just shuts off the island inverter and closes a relay to the grid, out of phase and causing a frequency jump, your microinverters might stay on line or might see grid instability.

When utility fails, depending on what is seen, I think Sunny Island may allow power to disappear for an indeterminate length of time.
When I open the knife switch, Sunny Island picks up quickly. Most equipment will ride through a lost cycle. Sunny Island has been keeping time, so it picks up in phase.

When reconnecting, Sunny Island does that smoothly, with gradual frequency shift. I'm not sure about voltage - they could adjust island voltage (RMS at least) to match as well, minimizing current through relay. Or maybe they just connect my typical 125/250V utility grid to 120/240V island.

When SMA has worked on something for me, they asked for history written to SD card. That lets them understand what took place, rather than going by my report/interpretation/opinion.

I get the impression SMA did not make a list of all requirements and then develop a sequence of tests to ensure the implementation met all. They may have when they developed the original models 20 years or so ago, but I keep finding exceptions now.

I've had a job where prime contractor submitted reports for compliance to each and every requirement. The process would require our staff of 20 to each review about 10 reports every day for a year. Not my cup of tea. Instead I got to dig in deep looking at a couple things that concerned me. Some took me a month to understand (switching to other issues until my thoughts congealed.) I certainly wouldn't have found every issue, but some things I raised were real and did get fixed eventually.
 
I am pretty sure the XW does shift phase and sync up to the grid before it connects. The LED lights don't even flick at all when I hear the contactor close. I'll bet the voltage and phase of the waves have to be within 2% as it connects. But I have never had it connect with the Enphase producing with the batteries full.

When I turn on the Enphase, after the 5 minute delay, they ramp up their power over about 10 seconds.
 
Hedges, I guess you figured it out, but I was curious what the settings for frequency were in the Sunny Boy. If you use the Sunny Explorer, you can change all the settings.

SB Frequency Monitoring.JPG
 
SMA support did respond, asked me to test with Sunny Boys in Island mode, see if frequency shift worked to reduce power output. If not, they would then look into the on/off grid switching by RS-485.
I tested that (with some inverters operating and some shut off, so enabling/disabling loads would toggle between insufficient/excess production) and frequency shift power control worked as expected.

I then repeated testing with standard UL-1741 settings. This time, I only observed Sunny Boys disconnecting when frequency was outside UL-1741 and they were in grid-tied UL-1741 mode. That occurred if I disconnected grid and Sunny Island dropped to 59 Hz (below 59.3 Hz), or if operating off-grid around 61.5 Hz (50% of available power requested) and I reconnected grid.

In the former case, after receiving command for off-grid, Sunny Boy reconnected because it switched to wider frequency range.

In the latter case, Sunny Island commanded Sunny Boy to switch from off-grid to grid-tied mode almost immediately after observing grid power; it didn't wait 5 minutes for stable grid. So Sunny Boys disconnected. With no power being produced, Sunny Island dropped to 59 Hz, which kept Sunny Boys offline. After 5 minutes Sunny Island synchronized frequency and reconnected. Later, Sunny Boys reconnected.

I wasn't able to reproduce the issue I thought I had observed. Might have only been during these transitions between grid/offgrid that it disconnected.

System back to frequency settings inspired by UL-1741-SA, seems to be working fine.
 
I'm also running a 30kW Sunny TriPower, with transformers for 277/480Y coming from 3x SI 5048US producing 120/208Y 3-phase.
The TriPower has default frequency shift power control range 61 to 62 Hz, like Sunny Boy. With UL-1741 setting, it disconnects outside 59.3 and 60.5 Hz. Supposed to have UL-1741-SA but don't see that, maybe a firmware update needed.

Sunny TriPower, with modified frequency range inspired by UL-1741-SA does ramp down power according to frequency. Only when Sunny Island disconnected from grid and able to shift frequency, of course. SMA's documentation says only on-grid or off-grid, not grid backup. Although it is supposed to have UL-1741-SA, they don't say it supports backup like the SB -40 and -41 models. Maybe that is because 30kW would exceed what it can feed-through Sunny Island (in UL 120V market). I find it does work, with smaller PV array so never too much power produced. Mine only has a single 120V phase connected because my service is 120/240V split-phase; I've connected less than 6700W. It should be able to backfeed 3-phase utility service with up to 20kW of PV. My future use could be entirely off-grid (except using grid as backup generator), in which case should support 30kW of PV plus overpaneling.
 
Ok. Was just wondering if one of the settings had the SB turn off at 59 hz.
Forgive me for asking, but what is the Tripower for? How can it be used in systems here?
3 of your SI6048 are wired for 3 phase power? The 4th is in parallel with one of the others?
 
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UL-1741 would have SB turn off immediately below 59.3 Hz or above 60.5 Hz.
UL-1741-SA lowers that to 58.5 Hz, so with that reduced limit SI's 59 Hz (to get clocks back on time) doesn't cause disconnect.

UL-1741-SA further widens the frequency range both higher and lower, ride-through for 299 seconds disconnect after 300 seconds. Or, frequency/watts.

I think 61 Hz is limit before immediate disconnect, so if mixing UL-1741-SA inverters with grid-backup Sunny Boys, would want to make the frequency-watts ramp end a bit below 61 Hz rather than SB standard 61 to 62 Hz.

TriPower is a 277/480Y 3-phase grid-tied inverter. The 30kW model can work with isolated 480V delta, while the lower wattage ones require the 277Y. It also has off-grid and frequency-watts mode. It will only operate if all three phases are present.

A more practical approach is 3x 208V Sunny Boys. But 3-phase inverter is interesting because it doesn't need to have bulk 60 Hz decoupling capacitors; power draw of 3-phase inverter is constant. Higher wattage available in smaller package at lower price.

My 4x SI 6048US are configured 2phase4, which is 2s2p (2p2s?) for 120/240V split phase and two in parallel each phase. Only 180 degrees apart, no 120 degree for 3-phase.

I have 3x SI 5048US, which I configured for 3phase, 120/208Y. That is Master, Slave1, Slave2. I tried telling one to be Slave4 hoping it would be synchronized with Master (for extra current by paralleling relays) or better yet split-phase at 180 degrees from Master. But Master reported an error, so a 4th SI can't be used on 3-phase.

For now the 3-phase setup is hanging inside by garage with 30A dryer cord connecting it to split-phase panel (only L1 connected.) Will replace with 6 awg and 70A breaker for 56A max single phase connection.

The TriPower is standing next to it, and with some MC3 connectors in a combiner I'm able to unplug a couple strings from my split-phase system and run a PV wire to the TriPower for testing. Later it will hang near the others with its fused disconnect switch. By switching off the PV strings I can swap wires if I want it going to the 3-phase.

The 3x SI 5048US setup serves as single to 3-phase converter, max 6700W input from grid plus surge from battery and up to 6700W from PV while grid-sell is enabled. Should support up to 30kW from PV and 15kW from battery if grid used only as generator (backfeed disabled.)

I've figured out how to create a 3rd phase given 120/208 just two legs 120 degrees apart (requires 2x SI). Of course from 1x SI (alone, or one of 2 or 3 with 120 degree phase shift), can make 120/240V split-phase, but that would be loading the same single phase, with wattage limit.

With 3x SI, I can use a couple transformers go create split phase from the two which are +/- 120 degrees, for double wattage split-phase. If each SI is 5kW, then I could get 10kW 240V. Windings connected together (auto-transformer) add voltage, a vector on the same line. Isolated windings make a parallel vector. Ideally, 3x 120V isolated windings. But typical transformer has 2x 240V and 2x 120V, all isolated. One 120V across a Sunny Island, and one (or two) 240V windings off its hot leg makes 120/240V split-phase (from that +120 degree or -120 degree phase slave.) Do that to both Sunny Island, then use the other 120V winding of each to make a vector off the other one's split-phase. Those two come together to make split-phase in line with the master. You've now got 120/240V 10kW split-phase or 120/208Y 15kW 3-phase from the same system.

I'd like to be able to grid-tie that split-phase, for 13.4kW to/from grid. May be possible, relay needs to be controlled in unison with Master SI's relay. Current transformer to sense current in L1 through relay is one non-invasive possibility. Signaling relay indicating on/off grid is another.
 
Ok. That's way beyond what I know. I see that you have 7 Sunny Islands then. I thought it was 4. That makes sense. Pretty complicated being your own power company.
 
12 ;) a

I bought one, expensive retail, planning to use it with transformer, also transfer switch, for 10kW of Sunny boys on grid and grid backup.
Then picked up 3 more that had been used for development of battery support of grid, 3-phase.
Then 8 more on a pallet (Thanks, DC Solar and Warren Buffet!)

You can figure out how to use transformers with a protractor and compass. Voltage is length of a vector, and phase is angle. One vector off the end of another to see what it produces. Or Trigonometry and Pythagorean theorem. Excel calculations and graphs. You can draw static arrows, but they are really rotating in a circle in the "complex plane" at 60 Hz. One axis is real (voltage) and the other is "imaginary". Projection of a vector on the real axis is instantaneous voltage. But you can do the math without imaginary numbers (represented as "i" or "j").

Using a 480V PV inverter adds the expense and weight of transformers. I see plenty on eBay, but located half way across the country, today's elevated shipping cost makes them less attractive. So better off with single-phase 208V GT PV inverters.

I had 3x toroid transformers I picked up, was able to use them as 120 to 260V auto-transformers, close enough to 277V to be within limits.
I want to get a bunch of 10kVA 240/480 to 120/240V transformers. With that I can use each 120V leg to make a 480V leg, for floating delta, and they're not too heavy to move with an appliance dolly. Two of the same could be used to make 3-phase from 2x 120V inverters that are 120 degrees apart, so one DC Solar trailer could make three phase with addition of just transformers, although 3rd Sunny Island would be preferred.

I rely on the power company, at least while I have NEM 1.0, for most storage.
I had an old AGM bank, now degraded from 100 Ah to 40 Ah, which I used for the 3-phase setup. Don't know how much starting surge that could supply.

I have a mountain property I thought this setup could be used for, which is why I picked up the TriPower when I saw it. Best sun would be hundreds of feet up the hill, so 277Vrms from ground would cut IR losses, while still being OK for 600V wire.

But I'm kidding myself. I just assembled the system because I could. Now I need to find some 3-phase loads bigger than my pool pump. I keep seeing air compressors at local auctions ...
 
Ahh. I remember you saying somewhere that you got a "pallet load" of SI's. Now I know you meant it literally! Wow. That would have been a lot had you had to pay retail! When I was looking, I was trying to decide between the Schneiders and SI and trying top justify the extra cost since I had to get 2. Not sure what made me do it, but I checked Craigslist and found a store selling them for $1600 each (instead of $4,000 each) so I got 2. Now with all this new NEM stuff I figured it might be good to get 2 more so I'd have 100A available. Got 2 more from the same place for $2500 each which is not bad for today.

I think you said you had NEM 1.0 for a long time now. Do you know what will happen when you hit 20 years? Will you go to NEM 2.0 or 3.0 or are you grandfathered in with NEM 1.0? Maybe I should post this as a new question. We are in our 20th year of "NEM" and not sure what will happen after that. PGE contract makes no mention of any sort for time limit.

This is all interesting stuff. Learning a lot here.
 
Yup, shrink wrapped pallet stacked 2 high with new in the box Sunny Islands. Seller turned around his inventory quick, while others remained to now at lower discount.
I saw another listing, 35 Sunny Island for $50k!

I also got a pallet of SB 5000US, liquidation from a dealer who had been selling CHP plants based on a diesel generator, which he couldn't get anymore. So I'm mostly using transformer type Sunny Boys now.

I have been grandfathered in NEM 1.0, was supposed to get transferred to NEM 2.0 terms (but without paying a one-time connect fee) at 20 years which is coming up soon.
NEM 3.0 as written, 15 years after connecting (or immediately if beyond 15 years), they were going to put me on 3.0 immediately. According to what CEC came up with, which is now on hold, would be taxed $8/kWh for (GT?) PV capacity, which works out to $0.05/kWh whether used immediately or exported. And I would be credited 25% of retail for export, which works out to $0.05/kWh (at least for rates at the time; lowest tier has been raised further.) That would have been a big fat $zero credit for all export, full retail for import, and a tax of $0.05/kWh for photons I use myself.
 
50K is not a bad deal if someone can find 8 other people top split it with.
I wonder how popular SI's would be w/o the big scam putting a lot of these in peoples hands at low prices? I would have had a hard time paying $8,000 for 2 of them.

I should have said that the end of our 20th year is coming up in a few mos. Is it possible we get to say in the same "NEM" as we have before? I write "NEM" because papers never mention "NEM 1.0" only "NEM" with true up at the end of every 12 mos after startup. Having to go to NEM 3.0 is what has me (and a lot of other people) concerned. Getting wholesale for what you feed in an paying retail for what you take out is really bad. NET over 12 mos is best for us since we can "bank" the extra winder power for use in the summer. So far we have been experimenting and the SI with frequency shift is working for us. Before we had/have NEM with (I think) $0.31/kwh noon to 6pm weekdays and $0.085/kwh nights and weekends. So for every kwh we put in to the grid during peak hrs, we could take out 3 1/2kwh and be even. So we ran all the heavy loads - water pumping, etc. at night and off peak. Now if we were forced to minimize grid back feed, we'd have to use the power as we generate it which means running heavy loads during the day. So far that works ok also. Water pumping, pool pumps, A/C washer, dryer, dishwasher, bread baking 240v oven we all do during the day now. So we got that figured out. Now need to see about power at night which means storage and that means some type of lithium battery probably. All depends on what the new rules will be. I have 2 more SI 's ready to go if we have to disconnect from PG&E entirely. Not looking forward to it because the grid is a really good "battery" for us now. Shifting power use is possible also. Irrigation during the day means more evaporation, but that is a catch-22.
 
I have been grandfathered in NEM 1.0, was supposed to get transferred to NEM 2.0 terms (but without paying a one-time connect fee) at 20 years which is coming up soon.
Sorry, one more thing. Not sure what you mean by "grandfathered" if you have to switch to NEW 2.0. If you were grandfathered in "NEM 1.0" would that not mean you stay in 1.0 "forever" (or until the service name changes/sell property)? If you have to change to 2.0 or 3.0 then you only got NEM 1.0 for 20 years which would mean not being "grandfathered in" but having a 20 year time limit? Or I am just not understanding it?
 
Grandfathered, but only for a while.

With NEM 2.0, there were changes to terms and a connect fee. Those of us with original NEM were supposed to get to keep if for 20 years from original date, then be switched to 2.0 (without the fee.)
I did pay a $300 fee for time of use meter (or maybe that was net metering meter), which was obsoleted and replaced at no charge with smart meter.

Something like grandfathered with original equipment requirement (I get to swap old inverters with other old or less old models, don't have to put in the latest standards.) And we were supposed to keep original terms for 20 years. The planned 3.0 was going to cut our time short. Not sure in the event we were already moved to 2.0, if that would immediately bump to 3.0 anyway.

Of course, $/kWh changed along the way, time of use vs. rate changed, and whatever tariff we were on was eliminated. They said we would automatically switch to a new one, or could choose an "even better" plan. Then San Jose was going to swallow up all customers, consumers first and PV producers second by default. They offered pricing just a smidgen better. I opted out, remained with PG&E. There was a form to check off, including "Why?", which included "Because I don't like being automatically switched."
In the event a customer turned out to be a deadbeat, they would be transferred back to PG&E. San Jose gets the profit of good customers, PG&E takes the loss of the bad? How can they do that?
 
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