<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi guys,<div><br></div><div>You might look into AC direct hydro controls. Thompson and Howe make them </div><div>they are designed to keep both frequency and voltage within tolerance with dump loads.</div><div><br></div><div>jay</div><div><br></div><div>peltz power<br><div><div>On Feb 12, 2013, at 5:13 PM, Glenn Burt wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Sounds like a job for a directional relay - utilities use them.<br><br>-----Original Message-----<br>From: <a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a><br>[mailto:re-wrenches-bounces@lists.re-wrenches.org] On Behalf Of Drake<br>Sent: Tuesday, February 12, 2013 7:29 PM<br>To: RE-wrenches<br>Subject: Re: [RE-wrenches] Generator Controlled Mini Grid<br><br>Hi Kevin,<br><br>Right now we are in the stages of investigating what is possible. The<br>design is for 10kW of PV - inverter capacity. The inverters will be Sunny<br>Boys, so if may be possible to regulate them.<br><br>We haven't decided on a generator yet. A dump load sounds like a good way<br>to absorb excess power.<br><br>Have you heard of electronic controls to facilitate this process?<br><br>Thanks,<br><br>Drake<br><br><br>At 03:43 PM 2/12/2013, you wrote:<br><blockquote type="cite">Hi Drake,<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Further, can you give us an idea what scale you are talking here - ie <br></blockquote><blockquote type="cite">PV and Generator capacity? With your mention of inverter/generator if <br></blockquote><blockquote type="cite">your talking ie the small Honda EU6500 or such?<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">I did think of another project that I am involved with - it's a remote <br></blockquote><blockquote type="cite">community with conventional diesel power plant (100 kW day,<br></blockquote><blockquote type="cite">30 kW night). There is 27 kW of distributed PV over 5-6 different <br></blockquote><blockquote type="cite">homes, using the older Xantrex GT inverters. It's not the most <br></blockquote><blockquote type="cite">elegantly designed solution - as it's possible for PV output to be <br></blockquote><blockquote type="cite">greater than the load which causes shutdowns. In that case, a dump load <br></blockquote><blockquote type="cite">is kicked in briefly and that bumps the frequency enough to kick the GT <br></blockquote><blockquote type="cite">inverters offline, and then the cycle repeats.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Not my design, but it does work and has been this way for several years<br></blockquote>now.<br><blockquote type="cite"><br></blockquote><blockquote type="cite">Kevin<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">-----Original Message-----<br></blockquote><blockquote type="cite">From: <a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a><br></blockquote><blockquote type="cite">[mailto:re-wrenches-bounces@lists.re-wrenches.org]On Behalf Of Drake<br></blockquote><blockquote type="cite">Sent: February 10, 2013 10:46 AM<br></blockquote><blockquote type="cite">To: RE-wrenches<br></blockquote><blockquote type="cite">Subject: Re: [RE-wrenches] Generator Controlled Mini Grid<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Hi Kevin,<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Thanks for the Eigg video. What a great place.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">I didn't see evidence of any AC coupling of inverter produced AC to a <br></blockquote><blockquote type="cite">generator produced mini grid. I understand this is being done in a <br></blockquote><blockquote type="cite">homebrew manner by some.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">The current wisdom on the issue is that the less the PV contribution to <br></blockquote><blockquote type="cite">the generator supplied grid is, the easier. It would seem that if a <br></blockquote><blockquote type="cite">grid tie inverter output could be regulated, using Sunny Island type <br></blockquote><blockquote type="cite">controls, it should be possible to have a small inverter generator <br></blockquote><blockquote type="cite">create a mini grid that could be fed by PV.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">A system featuring this type of technology was linked in a posting on <br></blockquote><blockquote type="cite">this list some years ago, The link seems dead now. In that case a <br></blockquote><blockquote type="cite">large generator was feeding a number of houses, and PV was fed into the <br></blockquote><blockquote type="cite">system.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">The reason for this interest is that battery backup systems are much <br></blockquote><blockquote type="cite">more expensive than generators. We need to find a way to utilize PV <br></blockquote><blockquote type="cite">arrays during outages without the expense of battery backup systems.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Drake<br></blockquote><blockquote type="cite"><br></blockquote><font class="Apple-style-span" color="#006312"><br></font></div></blockquote></div><br></div></body></html>