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--></style></head><body lang="EN-US" link="blue" vlink="purple"><div class="WordSection1"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546a">Hi Troy,</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546a"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546a">Have you double checked that your grounding systems both in the house and at the inverters/array are all up to snuff? </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546a"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546a">Sorry I can’t offer any help with the inductance issue.</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546a"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546a">Best,</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546a"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546a">August</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546a"> </span></p><div><div style="border:none;border-top:solid #b5c4df 1.0pt;padding:3.0pt 0in 0in 0in"><p class="MsoNormal">
<b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> <a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a> [mailto:<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Troy Harvey<br>
<b>Sent:</b> Tuesday, February 11, 2014 5:45 PM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] Long transmission line inductance and LED light flicker</span></p></div></div><p class="MsoNormal"> </p><div><p class="MsoNormal">
Richard,</p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal"><b>The system configuration is:</b></p></div><div><p class="MsoNormal">Approx 24.7kW of modules connected to:</p></div><div><p class="MsoNormal">
<span class="apple-tab-span"> </span>2 x 9kW Sunnyboys</p></div><div><p class="MsoNormal"><span class="apple-tab-span"> </span>1 x 5kW Sunnyboys</p></div><div><p class="MsoNormal">Plus</p></div><div>
<p class="MsoNormal">4 x 6kW sunnyislands, with</p></div><div><p class="MsoNormal">2 Parallel 48V Strings of (12 x 4V Surrettes ) using 350MCM cable</p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">
<b>Wire</b></p></div><div><p class="MsoNormal">The wire is about 1000 feet long 350 MCM in a "twisted" bundle to this outbuilding</p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal"><b>Conditions</b></p>
</div><div><p class="MsoNormal">The conditions were during the day with full sun, so during the test there is approx. 47kW of available inverter pointed at only >15 amps (120V) of load(!).</p></div><div><p class="MsoNormal">
The steady state conditions was a few LED lights, maybe 60 watts worth, plus a handful of vampire loads, maybe 100-200 watts total. When a pure resistance load, like a 1000W curling iron was turned on the lights would flicker.</p>
</div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">Since the lights flickered from a resistive load, but didn't stay dim, I assumed it was from a reactive-phase issues due to the transient turn-on - screwing with the LED dimmer circuits which are already doing a bit of magic to turn TRIAC waveforms into a DC constant current.</p>
</div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal"> </p></div><div><div><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:8.5pt">thanks,<br><br>Troy Harvey<br>---------------------<br>
Principal Engineer<br>Heliocentric<br>801-453-9434<br><a href="mailto:taharvey@heliocentric.org">taharvey@heliocentric.org</a><br><br></span></p></div></div><p class="MsoNormal"> </p><div><div><p class="MsoNormal">On Feb 3, 2014, at 8:33 AM, Richard L Ratico <<a href="mailto:Richard.L.Ratico@VALLEY.NET">Richard.L.Ratico@VALLEY.NET</a>> wrote:</p>
</div><p class="MsoNormal"><br><br></p><p class="MsoNormal">Hi Troy,<br><br>I'm assuming this is off grid. Could you please provide details for the system<br>(inverters, batteries, etc.). <br>A single, sudden, 20 amp load is not necessarily small relative to the size of<br>
the system. Is the load 120V or 240 V?<br><br>Dick Ratico<br>Solarwind Electric<br><br><br>--- You wrote:<br>On Sun, Feb 2, 2014 at 4:39 PM, Troy Harvey <<a href="mailto:taharvey@heliocentric.org">taharvey@heliocentric.org</a>>wrote:<br>
<br><br></p><p class="MsoNormal" style="margin-bottom:12.0pt"><br><br>We've got a PV system that has long lines from the inverters to the house<br>(1000 ft or so). While the wires are properly sized (2x350MCMs), it<br>
inherently has a lot of inductance due to the line-length. What We are<br>noticing is that dimmable LED lights flicker anytime a new load turned on,<br>even if that load is purely resistive and the overall current draw is small<br>
(20 amps or so). What I "think" is happening is the LED dimmer circuits get<br>their cue from phase delays, and that the inductance of the line length<br>causes some phase jitter everytime a load is applied - thus causing flicker.<br>
<br>Has anyone dealt with this issue successfully (other than switching<br>to incandescent lights)? Would a static capacitor bank at the house do the<br>trick, or do we need some type of active PFC? And if static did you have<br>
any issues with constant power draw from the capacitors?<br><br><br><br>Troy Harvey<br>---------------------<br>Heliocentric</p><p class="MsoNormal" style="margin-bottom:12.0pt">--- end of quote ---<br>_______________________________________________<br>
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