Is it possible to "island" Enphase inverters with generator

[fuzzelogic]

I've read about Sunny island by SunnyBoy which supposed to allow a generator and solar to function if power from the grid is not available.

Is there a system like that with enphase.

For example, at my house I have a backup generator that will come on 60 seconds or so after the power from the grid is lost and I'm not sure how or what will happen when using Enphase inverters with the generator that starts after power from the grid is lost???

[Sunking]

No there is not.

[fuzzelogic]

Thanks for the quick response!

So, in the scenario that I described, what will happen with the enphase inverters once the generator comes on?

Also, would you run your p.v. system with either the Sunny Island solution? OR would you try to run your system with the back-up generator providing power?

I'm aware the power will not be consistent as when coming from the grid compared to the generator.

[Naptown]

You would have to do an AC coupled system which gets very complicated and potentially expensive. It will also void the warranty on the Enphase.
In your situation you would need to tie the solar into the portion of the house that is NOT powered by the generator. If you have a whole house generator that has one big transfer switch for all the house such as a GE symphony etc then the solar will tie in on the line side of the transfer switch to keep it isolated from the generator. Under no circumstances can you have a generator and a solar system feeding your house at the same time unless you are using a hybrid type inverter and the generator is used for battery charging.

[shortcircuit2]

You would have to do an AC coupled system which gets very complicated and potentially expensive. It will also void the warranty on the Enphase.
In your situation you would need to tie the solar into the portion of the house that is NOT powered by the generator. If you have a whole house generator that has one big transfer switch for all the house such as a GE symphony etc then the solar will tie in on the line side of the transfer switch to keep it isolated from the generator. Under no circumstances can you have a generator and a solar system feeding your house at the same time unless you are using a hybrid type inverter and the generator is used for battery charging.

I totally agree. There are many systems out there that have slipped by inspection.

Here is another opinon...

Solar Photovoltaic with Generator Backup

Question: Can a grid tied-inverter be connected to a system that also has back up generator power?

Answer: Since a grid-tied inverter does not regulate its power output based on the load requirements it would try to push as much power into the house and the generator as it could when the house is isolated from the grid and something would have to break, be it the inverter or the generator. Which would go has to do with the relative impedances of the two sources and how robust the controllers were. Connecting to a generator would also probably invalidate the warranty of the inverter since all the grid-tied inverter manufacturer's I know specifically say not to do this.

The correct way to back feed in this situation would be to interconnect on the utility side of the transfer switch. I did have one job where we could not connect to the utility side of the transfer switch so I had to design a control system that used the auxiliary contacts in the transfer switch to control a contactor connecting the inverter to the main panel. When the transfer switch was in any position but utility supply the contactor opened and the inverter was isolated.

Sometimes you run into a client that wants to use the PV system when the utility is down, not an unreasonable request I think, but they usually change their mind when I describe what is involved in building a hybrid PV system verses a simple grid-tied system.


shortcircuit

[russ]

You must contact with the Enphase. That is a so bad quality!

Pardon? What do you intend to say?

[fuzzelogic]

Thanks for all the suggestions so far!

My generator is tied into the main break panel and there is a timer in the panel that will turn on the generator after 60 seconds or so after the power from the grid is disconnected. Above this switch doesn't get power and below will be powered from the generator.

The problem I have is though, when the power is provided from the electric company there is about a minute where the panel is in a in between state where half the power is coming from the grid and have from the generator until the switch that is open is closed again.

I would have about a 1 minute where the generator and electric grid could be providing some type of power to the main electric panel. Hopefully this will help with your suggestions! Thanks again for your comments

[Naptown]

Thanks for all the suggestions so far!

My generator is tied into the main break panel and there is a timer in the panel that will turn on the generator after 60 seconds or so after the power from the grid is disconnected. Above this switch doesn't get power and below will be powered from the generator.

The problem I have is though, when the power is provided from the electric company there is about a minute where the panel is in a in between state where half the power is coming from the grid and have from the generator until the switch that is open is closed again.

I would have about a 1 minute where the generator and electric grid could be providing some type of power to the main electric panel. Hopefully this will help with your suggestions! Thanks again for your comments

When power is restored the transfer switch will switch back after it senses stable grid power for a minute or so. When it does switch what you are hearing is the generator going through a cool down period. It is not connected to the grid at this time.
Secondly no grid tie inverter will start up immediately. There is a 5 minute start up sequence that it must go through before feeding anything to the grid.

[Sunking]

My generator is tied into the main break panel and there is a timer in the panel that will turn on the generator after 60 seconds or so after the power from the grid is disconnected. Above this switch doesn't get power and below will be powered from the generator.

The problem I have is though, when the power is provided from the electric company there is about a minute where the panel is in a in between state where half the power is coming from the grid and have from the generator until the switch that is open is closed again.

I would have about a 1 minute where the generator and electric grid could be providing some type of power to the main electric panel. Hopefully this will help with your suggestions! Thanks again for your comments

I hope you have a transfer switch.

[Naptown]

I hope you have a transfer switch.

He has an automatic and is referring to the cool down period on the generator which lasts about a minute.

[russ]

Should that switchover not be instantaneous? Mine is - no solar involved.

[Sunking]

He has an automatic and is referring to the cool down period on the generator which lasts about a minute.

OK my concern was

My generator is tied into the main break panel

[Naptown]

Most automatic transfer switches will wait a minute or so when the grid comes back up to make sure it is stable before disconnecting and returning the power to the grid. The generator will run for about a minute of so to cool down before shutting down.

[SunEagle]

Most automatic transfer switches will wait a minute or so when the grid comes back up to make sure it is stable before disconnecting and returning the power to the grid. The generator will run for about a minute of so to cool down before shutting down.

Standard procedure is to wait for a preselected time to check for normal power stabilization as well as phase synchronization.

[browser59]

I'm curious, If the enphase inverters can go in sync. with the utility , Why cant they do the same with a good whole house generater? Wouldnt the generater behave as if no load?