I had this issue way back with pvl's unisolar and it was always written off as hi pot leakage in the conductors and its good to see that it was put to paper On Mar 13, 2014 11:20 PM, "[email protected]" <[email protected]> wrote:
> > Interesting app note. Interesting problem. > > How far from this metal roof (grounded I presume) is the bottom of the > modules ? > > This app note is mainly talking about the area of the module from the > mounting bracket which should > be quite a bit less than the modules area from a distance above a grounded > metal plate like this roof. > > How far above the metal roof are the modules ? If they are real close, > raising them slightly might > be enough to lower that capacitance enough to stop the TL from tripping. > > Another thing you could do, but would of course cost money would be to > split the array up for > more inverters. > > This app says that 1400 nano-Farads is an approximate point for > problems. That's for 50 Hz. > It will be around 6/5 worse at 60 Hz. > > If you have a capacitance meter (impedance bridge or meter), you could > measure the capacitance > of the array. Disconnect the + and - from the inverter first of course. > Then, tie the plus and > minus of the combined array together and connect that to one terminal of > the capacitance meter. > Connect the other lead of the capacitance meter to the roof and/or ground > and it ~should~ show > the capacitance you are interested in. > > This is one of those newer compromises associated with the higher > efficiency TL inverters (anybody's, > not just SMA's of course), and also the newer code requiring TL > (non-isolated) inverters above 300 volts > and everything else new we have to all learn about. > > > Welcome to the future ! ( from Firesign Theater's "I think we're > all [solar] bozos on this bus" ) > > > boB > > > > > On 3/13/2014 7:31 PM, Marco Mangelsdorf wrote: > > Friends, > > > > We have run across an odd technical problem at our commercial install at a > laundromat on our island. Attached is the description of the issue from > SMA. We don't know much except that we are switch out the TL inverters to > the old style US inverters because SMA has no fix for the phantom ground > tripping. The issue is beyond our feeble understanding. > > > > Any observations to share? > > > > Thanks, > > > > marco > > > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: [email protected] > > Change email address & 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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