Re: [RE-wrenches] Generators and Grid-tie Systems

[Allan Sindelar]

Eric, The inverter output should connect to the grid, either at the meter or main panel, as if the generator isn't there. The critical (backed up) loads should be moved to a separate panel. Install feeders between the two panels, with a transfer (either/or) switch somewhere in the line. The transfer switch may be either manual or automatic. The grid feeds the main input of the transfer switch, the generator feeds the secondary output, and the critical loads panel is the common output. Be careful here - as Nick writes, things could get messed up quickly if you don't get it right. And don't rely on signage or the customer knowing what to do. Make it impossible to connect the two to each other. Allan Sindelar Allan@positiveenergysolar.com NABCEP Certified Photovoltaic Installer EE98J Journeyman Electrician Positive Energy, Inc. 3201 Calle Marie Santa Fe, New Mexico 87507 505 424-1112 www.positiveenergysolar.com Nick Soleil wrote: Hi Eric:     Did you notice my e-mail on this subject last week?  I was hoping that someone would have some new, more concrete information on this subject, but I guess the old story still applies.  Here is the basic run down.     The inverters will likely see the generator as utility power, especially if it is a decent quality generator, with a clean wave form.  The inverters will connect to the generator and back-feed the power into the generator's alternator, causing heat and generator failure.  The solar will burn up the alternator.  I have heard that this has occurred before.     The only way to prevent this is to connect the solar directly to the utility power (not through the generator's backed-up emergency load center.)      If you must connect the solar through the generator's emergency load center, then the generator must not be placed into "Auto," but must instead be in "manual."  The customer must be clear that the solar breakers must be turned off before the generator is turned on.  This probably should include signage which makes this clear to the customer.   Nick Soleil Project Manager Advanced Alternative Energy Solutions, LLC PO Box 657 Petaluma, CA 94953 Cell: 707-321-2937 Office: 707-789-9537 Fax: 707-769-9037 From: "solarepiph...@gmail.com" <solarepiph...@gmail.com> To: re-wrenches@lists.re-wrenches.org Sent: Mon, March 1, 2010 3:03:06 PM Subject: [RE-wrenches] Generators and Grid-tie Systems Hello, We have our first grid-tied install involving a propane generator coming up soon. No batteries. Customer will be getting a panel upgrade with the system. Specifically: 1.When sizing the replacement panel, do I have to account for the main, gen, and pv? 2.Will the pv sense the generator output as grid voltage and sync/output? 3.If so: during a power outage and while gen is operating, what if pv production is higher than the house loads? Thanks for the input! Eric Sent from my Verizon Wireless BlackBerry _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org

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