[RE-wrenches] Generator backfeeding enphase?

[Chris Mason]

While we are discussing this, I have a suggestion. We are using the Generac
Smart Management Module as a load management unit for generators. It
automatically senses that the power is coming from the generator. It has a
lock out mode, so it can be used to disconnect the inverter(s) when the
generator is running without needing any wiring. I anticipate this to save
a lot of cost and allow a more robust system when combining generators and
inverters.

On Tue, Oct 20, 2015 at 12:25 PM, Chris Mason <cometenergysystems at gmail.com>
wrote:

> He's wrong. Any inverter system will try to raise the voltage of the
> system, that's how grid tied inverters feed power to the load. With the
> utility grid, there is no issue as the inverter cannot move the voltage any
> significant amount (unless there is a high resistance point). With a
> generator which is also trying to feed the same load, as the inverter's
> output power comes close to the load, the voltage will rise and the
> generator's AVR will get confused. It will reduce the excitation to the
> alternator and will likely start to motor if the inverter's power output
> exceed the load. The generator can shut down if the the system voltage
> exceeds the high voltage setpoint, and other bad things can happen such as
> damage to the AVR and stator windings. There's no real way to know what
> will happen. In many cases where the load exceeds the inverter output,
> nothing bad happens, but it's a crap shoot.
>
> On Tue, Oct 20, 2015 at 12:01 PM, Howie Michaelson <howie at suncatchervt.com
> > wrote:
>
>> Does anyone think that there is no issue with having enphase potentially
>> backfeeding a backup generator? We almost always will tie in upstream of a
>> generator transfer switch, but a competitor is telling clients with an
>> enphase system there is no concern. Am I missing something?
>>
>> Thanks,
>> Howie
>> Howie Michaelson
>> NABCEP Certified Solar PV Installer™
>>
>> Catamount Solar
>> Renewable Energy Systems Sales and Service
>> VT Solar Electric Incentive Partner
>> http://www.CatamountSolar.com
>> 802-272-0004
>>
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>
>
> --
> Chris Mason
> NABCEP Certified Solar PV Installer™
> Solar Design Engineer
> Generac Generators Industrial technician
>
> www.cometsolar.com <http://www.cometenergysystems.com>
> 264.235.5670
> 869.662.5670
> Skype: netconcepts
>



-- 
Chris Mason
NABCEP Certified Solar PV Installer™
Solar Design Engineer
Generac Generators Industrial technician

www.cometsolar.com <http://www.cometenergysystems.com>
264.235.5670
869.662.5670
Skype: netconcepts
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