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Hybrid inverter with Microinverters

pat72

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Hi everyone, it's my first post so hopefully I won't make a fool of myself :)
Do all hybrid inverters provide the necessary voltage/freq to the microinverters in order to get them off their anti-islanding state after the grid goes out?
Or is it a matter of which software is loaded in a specific inverter?
From what I read, the anti-islanding feature is only required in the U.S so if I were to purchase a hybrid inverter overseas, I'm wondering if it will "know" how to get my microinverters back online during a grid outage.
Thank you
Pat
 
Hi everyone, it's my first post so hopefully I won't make a fool of myself :)
Do all hybrid inverters provide the necessary voltage/freq to the microinverters in order to get them off their anti-islanding state after the grid goes out?
Or is it a matter of which software is loaded in a specific inverter?
From what I read, the anti-islanding feature is only required in the U.S so if I were to purchase a hybrid inverter overseas, I'm wondering if it will "know" how to get my microinverters back online during a grid outage.
Thank you
Pat

Anti-islanding is a requirement everywhere :)
Hybrid inverter you mean that you want to sell power to grid with it, or a battery inverter ?
 
to sell to grid and have batteries as well. I have 32x 300W panels and 16 x YC600 microinverters (APsystems) so I'm looking at adding batteries + inverter/charger
 
to sell to grid and have batteries as well. I have 32x 300W panels and 16 x YC600 microinverters (APsystems) so I'm looking at adding batteries + inverter/charger

And you want to use the microinverters in a blackout to power your home :)
The easiest solution is with a Victron inverter. Multiplus II or Quattro.
You can connect a 48V battery to it. Separate MPPTs to charge the battery. Also can charge from grid or your microinverters.
It needs a box that separates your system from the grid in a blackout.
Victron starts producing power and controls your microinverters production with phase shifting.

Like this:
AC_coupled.jpg

Or if you want to have a protected load panel then UPS solution:
grid_tie_UPS.jpg

Or sell more to grid with a one unit hybrid and have protected load
hibrid.jpg

And even more possibilities :)
 
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I was looking at the Solark12K but I would need two (I want the whole house pass through) but 14K just for inverters is out of the question. So I found similar units in China but I want to make sure that I won't get stuck with inverters that don't have have the capability to get my microinverters back on line during grid outages. Was going to add two powerwall 10.5kw lifepo4 48V(also from China)
 
from Silicon Solar:
Anti-islanding protection is a US-required safety feature that is built into all grid-tied and hybrid grid-tie inverters that operate in the US. It may not be built into some inverters meant to operate in different countries.


which why I raised the question because if some inverters don't have this feature then maybe some inverter/charger also could be built without the capability to unlock a microinverter after grid outage
 
from Silicon Solar:
Anti-islanding protection is a US-required safety feature that is built into all grid-tied and hybrid grid-tie inverters that operate in the US. It may not be built into some inverters meant to operate in different countries.

Marketing ... I do not know a single country where anti islanding is not a requirement :LOL:

which why I raised the question because if some inverters don't have this feature then maybe some inverter/charger also could be built without the capability to unlock a microinverter after grid outage

The real question is what type of system do you want from the list above :)

1, power your microinverters, can have other mppts and solar panels (expensive)
2, is the cheapest but it does not power your microinverters
3, like second but can sell power
 
1629741137566.png

this one but only with the panel/microinverters and I'm not even sure it's the correct diagram because everything should go through the hybrid inverter first.
 

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This is the cheapest with Off-grid inverter. But in a blackout grid-tie microinverters will not work. Just the Off-grid inverters (and the loads behind it).
But you have a separate system for your house (extra PV if you like) and so you sell more power to grid.

With the green hybrid inverter you also can sell its PV's solar to the grid. (cost more) ... US? OK there is a little problem that this inverters for US are not UL listed, only the off-grid inverters ... sorry missed that :)
 
Not all hybrid inverters allow 'AC coupling" which is what backfeeding the hybrid inverter is usually referred to.

A hybrid inverter synchronized to input AC grid and closes its connect relay so inverter runs in parallel with grid.

AC coupling allows a battery-less Grid Tie inverter to backfeed into AC out of hybrid inverter up to the current limit maximum of the inverter connect pass through relay.

When grid goes down the hybrid inverter opens its pass through relay to grid. The hybrid inverter now acts like the grid for the GT inverters. Power from GT inverters continues to flow, based on sun level, to AC loads or backfeed into hybrid inverter to charge batteries.

The main issue is if the AC loads and any required battery charging power sums to less than GT inverter is putting out. Power has to go somewhere. In this case the hybrid inverter tweaks its output frequency to be outside the grid spec bounds causing to the GT inverter(s) to shut down, preventing overcharging the batteries. This is all or nothing on GT inverters, but is pretty much universal not dependent on a given manufacturer, as long as everyone obeys the GT specs.

There are systems where same manufacturer makes GT inverters and hybrid inverter that have more control on GT inverters power output. In this case it is common for either a comm bus interface so the GT and hybrid inverter can communicate or the GT inverter modulates their power output based on how far off grid frequency the hybrid inverter drives them.

The hybrid inverter freq movement is only a couple of Hz.
 
Not all hybrid inverters allow 'AC coupling" which is what backfeeding the hybrid inverter is usually referred to.

A hybrid inverter synchronized to input AC grid and closes its connect relay so inverter runs in parallel with grid.

AC coupling allows a battery-less Grid Tie inverter to backfeed into AC out of hybrid inverter up to the current limit maximum of the inverter connect pass through relay.

When grid goes down the hybrid inverter opens its pass through relay to grid. The hybrid inverter now acts like the grid for the GT inverters. Power from GT inverters continues to flow, based on sun level, to AC loads or backfeed into hybrid inverter to charge batteries.

The main issue is if the AC loads and any required battery charging power sums to less than GT inverter is putting out. Power has to go somewhere. In this case the hybrid inverter tweaks its output frequency to be outside the grid spec bounds causing to the GT inverter(s) to shut down, preventing overcharging the batteries. This is all or nothing on GT inverters but is pretty much universal not dependent on a given manufacturer, as long as everyone obeys the GT specs.

There are systems where same manufacturer makes GT inverters and hybrid inverter that have more control on GT inverters power output. In this case it is common for either a comm bus interface so the GT and hybrid inverter can communicate or the GT inverter modulates their power output based on how far off grid frequency the hybrid inverter drives them.
agreed, and the Solark 12K does all of that. I'm just not sure if the Deye or similar does it also of if this feature is proprietary to solark via its own software because it's made to be used in the U.S (anti-islanding).
 
agreed, and the Solark 12K does all of that. I'm just not sure if the Deye or similar does it also of if this feature is proprietary to solark via its own software because it's made to be used in the U.S (anti-islanding).
these units all use their "Generator" input to take in the AC from the microinverters but do they all send out the required volt/freq to the microinverters when the grid goes down to get them back online or is this feature only a Solark one (since they do their own programming/updates)?
 
agreed, and the Solark 12K does all of that. I'm just not sure if the Deye or similar does it also of if this feature is proprietary to solark via its own software because it's made to be used in the U.S (anti-islanding).
The all-nothing control on GT inverters is universal (assuming UL1741 certification). The variable frequency to GT power control is becoming more universal between manufactures but generally you have to pick a GT inverter that says it obeys that control of power output modulation. The variable power modulation on GT inverter makes it a bit harder for them to meet anti-islanding spec so they charge a bit more for the capability.

The all or nothing GT control is not that great of a handicap. Usually the biggest issue is max GT power that can be pushed through hybrid inverter pass-thru relay limit. In that case you can put some of the GT inverters on hybrid inverter output and others directly on grid. You will at least have the GT power available from ones on hybrid inverter output when grid goes down.
 
these units all use their "Generator" input to take in the AC from the microinverters but do they all send out the required volt/freq to the microinverters when the grid goes down to get them back online or is this feature only a Solark one (since they do their own programming/updates)?
Solark is doing something different than most hybrid inverters. If PV power is too much they just open the generator input relay that is used for the GT inverters connection shutting down all the GT inverters. They don't have to fool with AC freq shifting. Downside of this is now you have two pass through relays to go through by GT inverters when pushing to grid.

They are likely doing it this way because they are not low freq (heavy transformer) inverter. High freq inverters are more 'delicate' to surges.
 
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Does anyone in this forum have the Chinese version of the Solark12K or 8K working with a PV system using microinverters?
That's really all I need to know.
 
Does anyone in this forum have the Chinese version of the Solark12K or 8K working with a PV system using microinverters?
That's really all I need to know.
If not UL1741 SA certified, they shouldn't be.
 
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Does anyone in this forum have the Chinese version of the Solark12K or 8K working with a PV system using microinverters?
That's really all I need to know.
We do it for clients, it works. We've used it in a grid-zero configuration with the micros connected to the gen/micro-inverter input. Main loads are on the Deye's loads panel, fully backed up from the grid. Large loads non-critical on the grid panel, zeroed out if possible from the PV but are simply without power if the grid fails.

This is all or nothing on GT inverters, but is pretty much universal not dependent on a given manufacturer, as long as everyone obeys the GT specs.
GT inverter modulates their power output based on how far off grid frequency the hybrid inverter drives them
Most GT inverters made in the past few years are HECO 14H compliant meaning they are capable of derating based on frequency. Check with APsystems. They likely have a digi input trigger that can change modes on the micros so they respond to Deye's linear frequency shift when off-grid. It's a very simple configuration I'm sure. Will allow for very smooth control over the power output of the micros.

They had a white paper a while back for the YC500 but I believe the functionality is now available on all their micros. Just requires a few settings changes. We've been considering using them in conjunction with the Deye inverters on large distributed micro-grids (PV+Batt+Diesel) for the roof-mounted arrays on the outlier cabins.

https://emea.apsystems.com/wp-content/uploads/2018/03/APsystems_YC500_Victron-MultiPlus_2018_WP.pdf

If not UL1741 SA certified, they shouldn't be.
Deye's inverters are certified. See attached.
 

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I have 24 Enphase IQ7's and 4 ApSystems QS1's(the QS1's run 4 panels per inverter).....They are AC coupled to a Outpack GS4048 hybrid inverter that frequency shifts to shut them off once the batteries are full or we aren't using enough power in the house.

The Enphase inverters throttle back nicely and everything is seamless but the ApSystems QS1's do not throttle back. They put out power and when the frequency is changed they just shut off for 5 minutes and them come back on. The problem is it is an constant on and off cycle every 5 minutes because with solar panels, the output is usually 10 times more then our constant house power draw, and the power has no where to go.

I ran this way for a few power outages but the last 3 day outage I got sick of the on and off from the APsystems inverters and rewired them so they only work when the grid is present. I put them on the grid side of the inverter rather then the inverter output side where the inverter can frequency shift.
 
Deye's inverters are certified. See attached.

I don't see anything in that document claiming UL certification. It is a manufacturer self certification. "in accordance with" or "in compliance with" UL1741 is not UL1741 SA certification. In the end, it is if local ordinance inspector accepts any other certification.

I know UL and CE have cross approval agreements that are accepted by U.S. local ordinances.
 
I don't see anything in that document claiming UL certification. It is a manufacturer self certification. "in accordance with" or "in compliance with" UL1741 is not UL1741 SA certification. In the end, it is if local ordinance inspector accepts any other certification.

I know UL and CE have cross approval agreements that are accepted by U.S. local ordinances.
t looks to me that SGS can certify UL1741:
ttps://www.sgsgroup.us.com/en/news/2017/07/sgs-accredited-to-test-and-certify-to-ul-1741-supplement-sa

SGS ACCREDITED TO TEST AND CERTIFY TO UL 1741 SUPPLEMENT (SA) UNDER NRTL PROGRAM​


Jul 16, 2017

SGS has achieved recognition as an American Nationally Recognized Testing Laboratory (NRTL) and can now test and certify to the UL 1741 Supplement (SA) safety standard. This allows us to test and certify inverters, converters and other equipment for interconnected distributed generation in network support functions, making more intelligent and safe interconnections possible.
The second edition of the UL 1741 standard, issued in on September 7, 2016, distinguishes between two types of equipment:
  • Utility Interactive Inverter
  • Grid Support Utility Interactive Inverter (GSUI)
 
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