[RE-wrenches] 3 Phase Grid Tie with Battery Backup

Tue Feb 16 08:50:14 PST 2010

If you have 120/208 you have WYE.  How much power do you have to put into the grid?  The question if you need back up power what is it for?  if it is simple plug loads or lighting you might serve the customer well with single phase backup. If you need 3-phase back-up I find it hard to accept that they need it in one box. The Xantrex is three seperate inverters on one board that looks like 1 box.  The three 120 volt units make 120/208 three phase.    If you have 120/240 three phase you have Delta, high leg.  Other combinations of three phase are possible, but more rare. 

I am old and I have never seen a problem of 3 phase imbalance if I stay within 20% of the panel rating.  In fact I have seen single phase loads that will imbalance more than 20% not cause a problem.  The problem of imbalance is similar to what occurs with single phase and changed inverter rules to requireing a ground reference on 240 volt inverters.  This problem is that the neutral will get pushed off center voltage wise, I usually demonstrate this in my class.  YOu can not cause significat imbalance with three 120 volt inverters, but you could woty the old 208 no neutral inverters.  

Darryl   

--- On Tue, 2/16/10, All Solar Inc. Jeremy Rodriguez <allsolar at scswifi.net> wrote:

> From: All Solar Inc. Jeremy Rodriguez <allsolar at scswifi.net>
> Subject: Re: [RE-wrenches] 3 Phase Grid Tie with Battery Backup
> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
> Date: Tuesday, February 16, 2010, 9:27 AM
> 
> 
>  
> #yiv965209721 DIV {
> MARGIN:0px;}
> 
> 
>  
>  
> Yes, 
> No  Transformers,
> Single inverter. 
> 
> Another question, looking
> at the Fronius 10.1 and 
> 11.4-3, no battery backup of course, they both list
> 208v in the sizing 
> tool. I need to look at a manual, but I'm not sure
> if I would need 
> Delta, Wye, ..........
>  
> Thanks
> everyone!
>  
>  
> 
>   ----- Original Message
> ----- 
>   From: 
>   Rebekah 
>   Hren 
>   To: Allan at positiveenergysolar.com
> 
>   ; RE-wrenches
> 
>   Sent: Monday,
> February 15, 2010 5:34 
>   PM
>   Subject: Re:
> [RE-wrenches] 3 Phase Grid 
>   Tie with Battery Backup
>   
> 
>   
>   
>   Hi,
>   Does the utility mean by "match" that they
> don't want the inverter output 
>   transformed in any way? 
>   Could you not just use one 120V inverter? I've
> connected single 120 volt 
>   inverters (albeit not outback but I don't see why
> not) to a 120/208 wye 
>   without problems. You have to make sure the wires are
> sized correctly (solar 
>   pro had a recent article on unbalanced 3 phase wire
> sizing). This of course 
>   limits your backed up loads to 120V (w/out a
> transformer).
>   
> 
>   Rebekah Hren
>   North Carolina
>   
> 
> 
>   
> 
>   
> 
>   
>   
>   From: Allan
> Sindelar 
>   <allan at positiveenergysolar.com>
> To: RE-wrenches 
>   <re-wrenches at lists.re-wrenches.org>
> Sent: Mon, February
> 15, 2010 6:51:12 
>   PM
> Subject: Re:
> [RE-wrenches] 
>   3 Phase Grid Tie with Battery Backup
> 
> Yes you would. I don't 
>   believe there is a single inverter that meets the
> utility's wishes. 
> 
> 
>   
>   
> 
> 
> 
>   
>   Allan Sindelar
> Allan at 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
> 
> All 
>   Solar Inc. Jeremy Rodriguez wrote: 
>   Thanks Darryl, 
> Allen, would you have to use 3 
>     Sunny Islands?  one for each phase? 
> The Utility wants a single 
>     inverter. 
> 
> Jeremy 
> ----- Original Message ----- From: "Darryl 
>     Thayer" <daryl_solar at yahoo.com> 
>     
> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org> 
>     
> Sent: Monday, February 15, 2010 3:49 PM 
> Subject: Re: [RE-wrenches] 3 
>     Phase Grid Tie with Battery Backup 
> 
> 
> I do not know what is going 
>     on at Outback, but unless they reduced the product
> offering, they have the 
>     capability.  I have such a system. 
> 
> Use 3 of their 120 volt 
>     single phase inverters connected 3-phase WYE (120/208)
> 3 phase.  Each 
>     inverter is only a single phase, and you connect each
> inverter to the 
>     neutral and one phase, you program one to be the
> Master, and the others to 
>     be slaves on phase B and Phase C.  When you lose
> the grid, the Master 
>     inverter starts its sine wave and it generates the
> usual 60 Hz square wave 
>     on the Outback Bus and the following slave units delays
> the start of their 
>     sin waves by the appropriate 120 degrees to generate 3
> phases.  Each 
>     inverter picks up and makes 60 hz 3 phase. 
> 
> One thing, besure to get 
>     a rotation meter and check that you are generating
> 3-phase the same rotation 
>     as the grid. Else you will have big problems. (motors
> will reverse and you 
>     may fry the OB transfer relay) 
> 
> Next time you call outback ask a tech 
>     if you can slave the GVFX to make 3 phase, 
> 
> --- On Mon, 2/15/10, All 
>     Solar Inc. Jeremy Rodriguez <allsolar at scswifi.net> 
>     wrote: 
> 
> 
>     From: All Solar Inc. Jeremy
> Rodriguez <allsolar at scswifi.net> 
>       
> Subject: Re: [RE-wrenches] 3 Phase Grid Tie with Battery
> Backup 
>       
> To: starpower4u at juno.com, 
>       "RE-wrenches" <re-wrenches at lists.re-wrenches.org> 
>       
> Date: Monday, February 15, 2010, 4:14 PM 
> Jeff, 
> That was my 
>       first choice, but I was told by Outback 
> that they do not offer 
> a 
>       120/208 inverter(s). I have not set up a three 
> phase system yet, so 
>       bare 
> with me please. I was going to contact SMA next. 
> 
> Jeremy 
>       
> 
> 
> ----- Original Message ----- From: "Jeff Oldham"
> <starpower4u at juno.com> 
>       
> To: <Allan at positiveenergysolar.com>; 
>       
> <re-wrenches at lists.re-wrenches.org> 
>       
> Sent: Monday, February 15, 2010 3:03 PM 
> Subject: Re: [RE-wrenches] 
>       3 Phase Grid Tie with Battery 
> Backup 
> 
> 
> > You can also do 
>       it w/Outback up to 10.8kW 
> > 
> >>From the Solar, Wind and 
>       Hydro powered office of 
> Jeff Oldham/Regenerative 
> >>SOLutions 
>       
> 
> 
> 
>   
> 
>   
>   
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