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Allan,<br>
<br>
It isn't easy to find the rational info about this topic amongst the
mountain of irrational scare and hype.<br>
Consider reading about solar disturbances on <a
href="http://news.nationalgeographic.com/news/2011/03/110302-solar-flares-sun-storms-earth-danger-carrington-event-science/">National
Geograpic News</a> and <a
href="http://en.wikipedia.org/wiki/Geomagnetic_storm">Geomagnetic
storms on Wikipedia</a>.<br>
Then read a little about nuclear blast EMP on <a
href="http://en.wikipedia.org/wiki/Electromagnetic_pulse">Wikipedia</a>
or many other places.<br>
Shake this together and you start to reach the scare and hype that
shows up on survivalist blogs.<br>
Yes, it is possible for there to be problems. Power and communication
systems have been disrupted by geomagnetic storms before. Power and
communication systems will have trouble again. Homeowner inverter
systems probably won't have any trouble at least not any serious
trouble. Yet you can't rule out the possibility that some of them will
experience some sort of damage. <br>
<br>
Communication systems depending on radio wave propagation will
certainly experience interference. Some frequencies will be worse than
others. Since intense radio interference can cause electronic devices
to misoperate, inverters are potentially at risk too. Since the
corneal mass ejection, CME, arrives a couple days after the visible
solar flare, there is time to prepare and it would be wise to shut
things down for the arrival of the CME. IMHO, the risk to solar or
battery based inverter from a solar burst is not very great.<br>
<br>
Wire based communication systems, pipe line systems, and electric power
systems are exposed to telluric or earth currents, see <a
href="http://en.wikipedia.org/wiki/Telluric_current">telluric current
on Wikipedia</a>. To understand why these are a problem, a couple
popular misconceptions about earth must be corrected: 1) the earth
isn't zero resistance 2) the earth potential isn't the same everywhere.
Even copper which is a much better conductor than the earth has
resistance! The earth is more akin to large piece of inhomogenous
resistive material that we make connections to by poking electrodes
into it; much like the doctor sticks electrodes on your chest and back
for an EKG. And current flows through this huge resistor system:
telluric current, galvanic current, current from cathodic protection
systems, current from some electric power systems. So the earth can't
possibly all be the same potential. Now take two grounding electrodes
that are many miles apart: they certainly are a different potential. If
connected by a conductor, current will flow through it - usually just a
small current. In an EMP event, the telluric current can suddenly and
dramatically change. Possibly change to damaging quantities but more
often in a manner that causes power system protection relays to trip
lines off unnecessarily. Consider two grounding electrodes a few
hundred feet apart - the telluric current isn't likely to be large
enough to cause any problem.<br>
<br>
No electronic communication means no banking, no commerce, no police or
fire protection, no internet. By gosh it could be the end of society as
we know it. Sell the survivalist a spare inverter and charge controller
(all sales final - no returns allowed - because they will probably want
to return it after the solar maximum).<br>
<br>
Kent Osterberg<br>
Blue Moutain Solar, Inc<br>
<br>
<br>
<br>
<br>
Allan Sindelar wrote:
<blockquote cite="mid:4D84EEBF.1090507@positiveenergysolar.com"
type="cite">
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For those of us less aware of solar flare issues and what we might
expect that relates to PV, could someone provide a good link to educate
us?<br>
Thanks, Allan<br>
<br>
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<font face="Times New Roman, Times, serif"><b>Allan Sindelar</b></font><br>
<small><a moz-do-not-send="true"
href="mailto:Allan@positiveenergysolar.com"><font color="#000099"
face="Times New Roman, Times, serif"><u>Allan@positiveenergysolar.com</u></font></a></small><font
face="Times New Roman, Times, serif"><br>
<span style="font-size: 10pt;">NABCEP Certified Photovoltaic Installer<br>
NABCEP Certified Technical Sales Professional<br>
New Mexico EE98J Journeyman Electrician<br>
<b>Positive Energy, Inc.</b><br>
3201 Calle Marie<br>
Santa Fe, New Mexico 87507<br>
<b>505 424-1112</b><br>
<a moz-do-not-send="true" href="http://www.positiveenergysolar.com/"
target="_blank"><u>www.positiveenergysolar.com</u></a><o:p></o:p></span></font>
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style="font-size: 10pt;"><font
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</span> </div>
<br>
On 3/19/2011 11:48 AM, R Ray Walters wrote:
<blockquote
cite="mid:2E505306-9D57-42A2-802E-95CA6C798920@solarray.com"
type="cite">Hi Drake;
<div><br>
</div>
<div>No, I don't have answers, just more of your same concerns. I
had a high altitude (12,500 ft) installation damaged recently, possibly
by a solar flare in Feb; we lost a C40 charge controller. </div>
<div>At this point, I don't know if the flare was the cause or not,
but I would expect more problems at higher altitudes.</div>
<div>So far, my internet research says that the panels and
batteries would be ok, but we might expect damage to electronics
similar to the induced high voltages caused by lightning.</div>
<div>Would grounding help? (I, too, also considered the Faraday
cage....)</div>
<div><br>
</div>
<div>NASA is predicting the solar storm of a generation for
2012-2013, and I read of a similar EMP incident in the 1800s that set
telegraph equipment on fire. </div>
<div>I think very long utility lines and transformers at the ends
of those lines are the most vulnerable, so this could be more of
GridTie issue?</div>
<div><br>
</div>
<div>
<div> <span class="Apple-style-span"
style="border-collapse: separate; border-spacing: 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-indent: 0px; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px;">
<div>R. Walters</div>
<div><a moz-do-not-send="true" href="mailto:ray@solarray.com">ray@solarray.com</a></div>
<div>Solar Engineer</div>
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</div>
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<br>
<div>
<div>On Mar 19, 2011, at 8:53 AM, Drake wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">
<div> Hello Wrenches,<br>
<br>
I had an inquiry concerning the effect of EMP on photovoltaic systems.
We are heading for a period of solar activity that likely will produce
this effect. According to a local AEP (American Electric Power)
representative, the utility is spending a lot of money to counter this
anticipated problem. Additionally, nuclear related issues are moving
back to the front burner. <br>
<br>
It is clear that the pulse would damage an inverter, but possibly it
could be put in a Faraday cage. But a number of questions arise.
<ul>
<li>Would the pulse damage the modules? </li>
<li>Could the large currents and voltages induced by EMP damage
the conductors in the cells? </li>
<li>Even if the inverters were surrounded by a Faraday cage,
would induced currents & voltages from the modules harm the
inverters?
<ul>
<li>Would series fuses and surge protectors be adequate
protection. </li>
</ul>
</li>
</ul>
Has any research been done in this area? Does anyone know answers to
any of these questions?<br>
<br>
Thanks,<br>
<br>
Drake <br>
<br>
<x-sigsep> </x-sigsep>
<p> <font color="#0000ff">Drake Chamberlin<x-tab> </x-tab>
<br>
Athens Electric<br>
OH License 44810<x-tab> </x-tab><br>
CO license 3773<br>
NABCEP Certified PV<br>
</font></p>
</div>
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