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Hi Eli,<br>
I'd agree with Keith that some caution is in order here.<br>
<br>
This is a picture of my Enphase PV array with some modest shading:<br>
<a class="moz-txt-link-freetext" href="http://www.builditsolar.com/Projects/PV/EnphasePV/Shading.htm">http://www.builditsolar.com/Projects/PV/EnphasePV/Shading.htm</a><br>
<br>
You can see from the real time output plot that even the panel with
just a line across it is very much effected.<br>
The shadow is wider than a power line would cast, and maybe the
effect would diminish as the shadow gets narrower, but I'd be
careful.<br>
<br>
If I think about it later today and the weather cooperates, I'll set
up narrower shadow and let you know how that comes out.<br>
<br>
The micro inverters are good in that a shadow across one module only
effects the output of that one module and not the whole string, but
a wire shadow that goes across several modules could still have a
serious effect.<br>
<br>
Gary<br>
<br>
<br>
On 12:59 PM, Keith Winston wrote:
<blockquote
cite="mid:%3CBANLkTikWHTbcWvMu9ZoG2i53g00zenTYfQ@mail.gmail.com%3E"
type="cite">I'm not quite sure what you mean by "smaller than the
sun's disc"... larger power lines can cast distinct shadows. If
those align with an axis of the modules, then they may shade an
entire row of cells in a module, overcoming the ability of the
bypass diodes to "bypass" the shaded cells (most modules are, I
believe, still bypassed on a cell-by-cell basis, and are wired in
series along one of their axis). So I'll stand by my earlier
comment that a power line could very well create significant
shading. But I agree with the microinverter suggestion.<br>
<br>
Keith<br>
<br>
<br>
<div class="gmail_quote">On Mon, Apr 4, 2011 at 11:22 AM, Gordon
Howell -- Howell Mayhew Engineering <span dir="ltr"><<a
moz-do-not-send="true" href="mailto:ghowell@hme.ca">ghowell@hme.ca</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">
Thanks for your question Eli:<br>
<br>
It doesn't appear that the electrical lines would be a
significant issue. They are likely smaller than the sun's
disc.<br>
<br>
If you use Enphase module-inverters (one inverter for each PV
module) then any shaded module wouldn't affect the PV array's
performance, because each PV string is a PV module.<br>
<br>
To clarify: the industry term that is an
internationally-recognised standard for PV modules is
"module", not collector, not panel. See attached file for
pictoral description.<br>
</blockquote>
</div>
<br>
</blockquote>
<br>
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