[RE-wrenches] grid-tie solar behind a generator

[Benn Kilburn]

I had a similar scenario a few years ago and looked at the Generac SSM, but for some reason(s) I cannot recall, could not go this route. 
The system was on a house and the auto transfer switch and generator were in a shack that was unreasonable to trench too, and we did not want to rely on a wireless option. 

The solution we came up with was a contact that would disconnect the inverters from the house panelboard upon a loss of voltage (grid). 
Unfortunately we did not come up with a solution that would automatically reconnect the inverters once the grid was restored... because we couldn’t reliably distinguish between the generator and the grid, so it required a manual reset once the customer could confirm they had grid power and not running off the generator. 
The client said they often did not know that there was a power outage so there could be times they would not even know the inverters had shut off... so I ran a low voltage line to a LED light in their kitchen area that would come on upon loss of grid and would go out when the inverters were manually reset. 

Benn Kilburn
SkyFire Energy
780-906-7807

> On Feb 25, 2021, at 6:40 AM, Nik Ponzio, Building Energy <nponzio at buildingenergyus.com> wrote:
> 
> We are installing 25kW of PV on a service with an existing backup generator (Eaton 30KW) and auto transfer switch. Because of the remote location of the generator and transfer switch, we can not easily connect on the grid-side of the transfer switch as we usually do (without cutting a very long trench.) So we're looking for a way to lock out the solar during generator use. And then, ideally, reconnect the solar automatically when the grid is restored. 
> 
> Is there an off-the-shelf product available at this point to accomplish this? 
> 
> I see a thread on here from a couple years ago that recommended the Generac SMM for this type of scenario. Any current thoughts on this approach?
> 
> Any suggestions would be appreciated.
> 
> 
> --
> Nik Ponzio 
> Building Energy
> 1570 South Brownell Road
> Williston, VT 05495
> direct: 802-318-7003
> nponzio at buildingenergyus.com
> http://www.BuildingEnergyVT.com 
> 
>  
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