Solar Inverter Lab

[C222]

Hey everyone, given the recent video, I thought everyone would enjoy a look at the solar inverter lab I have access to.


First, an overview:
On the far left there is a breaker panel connecting the grid (three-phase 208V) to our PV simulators and power transformer.
Below the breakers is a pair of DC PV simulators.
In the middle there are the eight inverters currently being tested.
On the right, there is a power transformer connecting the left breaker box to the residential (two-phase 240V) breaker box. The restdential breaker box is connected to all the inverter outlets and some test loads (fans, heaters, a microwave).

The commercial breaker panel:


Two Chroma 62000H-S Solar Array simulators:

They can act like a normal DC power supply and also simulate the effects of shadows, clouds, and a day cycle.

The power transformer taking the commercial circuit down to a two-phase 240V circuit that all the test loads and solar inverters are hooked up to:

On top there is an SEL-735 Revenue Meter to monitor the overall power that the loads are drawing from the rid+inverters. The inverters all have internal power measurement built in as well.

The inverters are:

• ABB PVI-5000
• ABB PVI-3.0
• Fronius IG Plus
• Fronius Primo
• SolarEdge SE6000
• SolarEdge SE6000A
• Schneider Electric Conext
• Delta Solivia 3.0TL

Open to any questions or requests for better images (not taken with a phone).
I'm the communications guy, so I can answer those questions easily. I can forward any electronics-related questions to my coworker.

[Phoenix]

My first question would be Whats the purpose of the lab? Reverse engineering, compliance, testing under unusual cases? There is no measurement equipment connected...

The inverter wall at my work only has 3 models (a couple more sitting around somewhere), and we only have 1 power supply capable of PV emulation. "know thy enemy"...

[C222]

"know thy enemy"...

Hey, we're all in this together to keep the fossil fuels in the ground. That being said, nothing here should really be a surprise.

I use this lab to test communications between all out different devices we deploy in the field.
We also test the inverters how they respond to different fault conditions.
We have a guy who does all the testing and teardowns to check the quality of prospective inverter suppliers, but he's not really the type who'd be interested in keeping up with a YouTube channel. Also, he keeps all the test equipment tucked away in a corner.
For my purposes, the inverter's internal measurements and the SEL meter are enough for me.

What inverters are you guys running?

[LabSpokane]

I'd be interested in how you're handling the comms. Are you backhauling the data somewhere or does it remain at the client site?  I'm assuming that you are a commercial, residential solar provider, correct?

I see a lot of string inverters. Do you field microinverters as well?

Do you provide generation data to the utility or is this just for your use only?

[C222]

We slurp all the data up into a huge database for the customer to see and brag about, just like how Dave is using http://pvoutput.org/. We also have realtime capabilities to know how the system is operating right then.

We do commercial and residential.

We don't field microinverters. IIRC they ended up costing too much for residential installs when compared to a string inverter, communication is much more complex, and it's easier to replace a single faulty unit then it is to locate the faulty microinverter and replace that. Anything to keep someone from having to go and work on a customer's roof.

It's for us and the customer. It's how we bill and how they can see their money's worth.

[Phoenix]

"know thy enemy"...

Hey, we're all in this together to keep the fossil fuels in the ground. That being said, nothing here should really be a surprise.

What inverters are you guys running?

I was more suggesting if you were an inverter manufacturer you'd like to know what the competition is making rather than the competition being oil. At the moment we have an Enasolar, a Sharp and our prototype running, got a CMS and I'm sure we had an SMA kicking around somewhere.

For PV emulation we have a Magna Power TSD1000-15 (1000V 15A) and XR600-9.9 (600V 9.9A). We also have/had access to a California Instruments CX30 30kVA? 3ph 4 quadrant AC "grid emulator" at another place. Not quite as much as you guys.

[C222]

"know thy enemy"...

Hey, we're all in this together to keep the fossil fuels in the ground. That being said, nothing here should really be a surprise.

What inverters are you guys running?

I was more suggesting if you were an inverter manufacturer you'd like to know what the competition is making rather than the competition being oil. At the moment we have an Enasolar, a Sharp and our prototype running, got a CMS and I'm sure we had an SMA kicking around somewhere.

For PV emulation we have a Magna Power TSD1000-15 (1000V 15A) and XR600-9.9 (600V 9.9A). We also have/had access to a California Instruments CX30 30kVA? 3ph 4 quadrant AC "grid emulator" at another place. Not quite as much as you guys.

Well, if you want to kick everyone's butt in my opinion. Throw on a ZigBee modbus (sunspec) interface that updates at 1 Hz at least and incorporate a revenue-grade power meter (ANSI C12.1).

Our lab is for shopping for inverters, not testing our own inverter.

[KD0CAC John]

I have been into solar and other alternative sources of power & fuel for a few decades and got into ham radio about 8 yrs. ago , and have been seeing lots of questions about RFI / noise into the radio gear .
And have not been getting much on inverters , of quality that are low on RF nose , so asking if that may be one of the things you would have info on ?
Thanks
John

[C222]

I have been into solar and other alternative sources of power & fuel for a few decades and got into ham radio about 8 yrs. ago , and have been seeing lots of questions about RFI / noise into the radio gear .
And have not been getting much on inverters , of quality that are low on RF nose , so asking if that may be one of the things you would have info on ?
Thanks
John

From what I've heard, the bad interference is pretty localized. But I've heard some stories. We knocked out some poor customer's garage door opener because we installed it too close in their garage.

But hey, as long as the antenna is outside the metal case, 2.4 Ghz punches right through any interference.

I'll take my SDR into the lab tomorrow and take a shot of the spectrum.

[KD0CAC John]

A good source of info for me , use to be Home Power Magazine , http://www.homepower.com/
I talked to them and they did not have experience with the issue .
In there earlier decades , they use to give good reviews / or bad if deserved , but it seems the last decade or so they seem to keep away from any negative info .
 
 

[LabSpokane]

I would have thought a residential string inverter would have to be a FCC class B device. Is this not the case?  Are people leaving the enclosures open or something to cause the RFI?

[KD0CAC John]

The FCC is not doing anything to speak of , finding all kinds of gear that seems to be causing RFI issue for some yrs. now .
Many of the better brands names are known to cause noise , at least that has been info gathered from others , like QRZ forums group - ham radio site .
I have not had my radio near any of my inverters  [ near with same building ] manly because I haven't been using solar in my living space since I have been a ham , about 7-8 yrs.
Getting close to wanting to have solar again , so looking again to see inverters are suggested , rather than spend $1,500 - $3,500 and find out after .
Not just plain cheap inverters , but grid-tied & battery charging inverters .

[mtdoc]

Getting close to wanting to have solar again , so looking again to see inverters are suggested , rather than spend $1,500 - $3,500 and find out after .
Not just plain cheap inverters , but grid-tied & battery charging inverters .

I would pose your question on the Midnite Solar Forum

Midnite's chief EE designer Bob Gudgel and their chief technical support person Ryan (Halfcrazy) are both Hams and post there regularly.  Midnite mostly designs and sells charge controllers (though they have an inverter in the works) but Bob was one of the chief designers of the legendary Trace inverters and the Outback Power inverters.  Those guys would likely know which inverters are quietest RF wise.

[C222]

Well, I tried my best with my $20 SDR. Couldn't find much interference coming from the inverter that we had running.

I had to get the antenna right next to it to see anything in the hour I had before a meeting.

Unfortunately my SDR cant go lower because that's probably where the majority is. It seems pretty quiet >80MHz.

[KD0CAC John]

Your scan misses a lot of ham bands below 25Mhz & above VHF , UHF .
Since I have not had the issue , just many that have had both ham radio & solar / inverters , I am lacking lot of detail .
How many different inverters have your tried this with and what are the make & model ?
Thanks for your efforts .

[mairo]

Nice to see you using Chroma gear. How do you run the two units - parallel/serial? Are you using Chroma's soft panel, or your own software?

[KD0CAC John]

I guess no updates on RF quite inverters ?