solar, utility power and a gen
- Thread starter G._S._Ohm
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jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
SMA's Sunny Island inverter is capable of acting as the brain for such a system.
http://www.altestore.com/store/descfiles/sma/island/Island_in_use.jpg
Outback products can do everything except the wind part. Also some of the Xantrex and Magnum products.
There are a lot of distinct issues that come up depending on system design. All of these products have various programming options that require attention.
AC coupled inverters must be shut down or have their power limited if the grid is down and the generator turns on. Usually this is done with frequency shifting.
http://www.altestore.com/store/descfiles/sma/island/Island_in_use.jpg
Outback products can do everything except the wind part. Also some of the Xantrex and Magnum products.
There are a lot of distinct issues that come up depending on system design. All of these products have various programming options that require attention.
AC coupled inverters must be shut down or have their power limited if the grid is down and the generator turns on. Usually this is done with frequency shifting.
SolarPro
Senior Member
- Location
- Austin, TX
AC coupling is a very attractive way to go with that many inputs. Here's a detailed discussion of some of the issues involved and the relative capabilities per manufacturer:
http://solarprofessional.com/article/?file=SP5_5_pg74_Schwartz&search=
http://solarprofessional.com/article/?file=SP5_5_pg74_Schwartz&search=
Last edited:
tallgirl
Senior Member
- Location
- Glendale, WI
- Occupation
- Controls Systems firmware engineer
I believe the OutBack FM60 and FM80 will do wind, but not as well as the Midnite Solar Classic which has the ability to define power curves for wind.
It's not the case that AC coupled inverters have to reduce their output when a generator comes on. The only requirement is that the system has to have diversion or production control so that the batteries aren't over-charged.
There are a lot of issues trying to add a generator to a grid-interactive system, not the least of which is the potential to ruin the generator of the output is grid-quality and the inverters try to export power back to it.
All in all, sounds like a fun install with many challenges.
It's not the case that AC coupled inverters have to reduce their output when a generator comes on. The only requirement is that the system has to have diversion or production control so that the batteries aren't over-charged.
There are a lot of issues trying to add a generator to a grid-interactive system, not the least of which is the potential to ruin the generator of the output is grid-quality and the inverters try to export power back to it.
All in all, sounds like a fun install with many challenges.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
That's what I meant (the system has to have the ability to disconnect or reduce production).
tallgirl
Senior Member
- Location
- Glendale, WI
- Occupation
- Controls Systems firmware engineer
In practice, it is far more complex. Not all inverters respond (well) to frequency shifting, and for many AC coupled products, you'll trip out on UL 1741 limitations if the main inverters changes the frequency -- unless that's what you want. But if you design the system so the AC coupled inverters disconnect, you can lose a substantial amount of energy production, which then has to be made up by the generator.
There are advantages to having AC coupled inverters, notably they make AC power in the first place. However, if the system design is "disconnect the AC coupled inverters", you lose the primary benefit of AC coupling and DC PV is probably a better solution. Unless you happen to have a thing for SMA inverters and Sunny Islands.
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