Author Topic: EMP effect on solar arrays??  (Read 13946 times)

Fred_47460

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EMP effect on solar arrays??
« on: June 25, 2009, 07:23:00 PM »
Does anyone have a clue as to the effect of an EMP pulse on a solar panel (PV array) ??  I imagine that the batteries in an off-grid system would survive. The charge controller and any inverter equipment would be toast....but copies of them could be stored in a Faraday Cage. But I've NO CLUE as to the effect on the PV array.

Offline “Mark”

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Re: EMP effect on solar arrays??
« Reply #1 on: June 25, 2009, 07:47:16 PM »
Solar cells are basically reverse LEDs. I imagine they would be fried.
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Fred_47460

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Re: EMP effect on solar arrays??
« Reply #2 on: June 26, 2009, 06:14:29 PM »
Well heck. I've been researching the effect EMP might have on solar panels (PV....which means Photo-Voltaic). Some sites say "Yep, their toast"....and you guessed it....some sites say "Not a problem on the panels themselves". Such as: http://2012.feedables.com/story/3210114/Letter-Re-Questions-on-EMP-Protection
I guess it doesn't really mean much to what I want to accomplish. I think the solution of wrapping stuff in foil, then plastic, then foil, then plastic, and stuffing it in a metal trash can with a tight fitting metal lid is an awesome idea. I can fit a couple radios, and a small solar battery charger to charge batteries for the radios in a can and be done. I can't afford a full-size off-grid system right now anyway.

Juggernaut

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Re: EMP effect on solar arrays??
« Reply #3 on: June 26, 2009, 06:19:33 PM »
if you wrap the equipment in tinfoil and plastic layers, it could form a capacitor, an electronic device that stores energy. I imagine that this would have a negative effect on the solar array. i would protect it with a thick layer of magnetically permeable metal, such as iron to absorb the magnetism, making its effects on the equipment lower.

Fred_47460

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Re: EMP effect on solar arrays??
« Reply #4 on: June 26, 2009, 06:37:39 PM »
if you wrap the equipment in tinfoil and plastic layers, it could form a capacitor, an electronic device that stores energy. I imagine that this would have a negative effect on the solar array. i would protect it with a thick layer of magnetically permeable metal, such as iron to absorb the magnetism, making its effects on the equipment lower.

Another method I came across in my research is putting the stuff in an old microwave oven (apparently, they have quite good shielding) and burying it a couple feet deep. This may seem extreme, but I'll bet it'd ABSOLUTELY work!!

Juggernaut

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Re: EMP effect on solar arrays??
« Reply #5 on: June 26, 2009, 07:21:43 PM »
I don't think it will help burying the solar panels.  :P jkjk! so you bury the components underground by your house, or wherever the solar panels are at?

Fred_47460

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Re: EMP effect on solar arrays??
« Reply #6 on: June 26, 2009, 07:32:07 PM »
I don't think it will help burying the solar panels.  :P jkjk! so you bury the components underground by your house, or wherever the solar panels are at?

This was an idea a friend of mine at work said he uses. Bear in mind....I'm not considering burying LARGE items.....just basically a microwave oven with a couple radios, and a small solar battery charger placed INSIDE the microwave oven. As for you not thinking it would help...I'm a bit mystified...what possible better ground system than THE GROUND ???

Juggernaut

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Re: EMP effect on solar arrays??
« Reply #7 on: June 26, 2009, 07:42:37 PM »
oh, I do think it will work! I just didn't understand what you meant, but that does sound like a good idea!

Offline Steve W

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Re: EMP effect on solar arrays??
« Reply #8 on: August 04, 2009, 04:16:47 PM »
Does anyone have a clue as to the effect of an EMP pulse on a solar panel (PV array) ??  I imagine that the batteries in an off-grid system would survive. The charge controller and any inverter equipment would be toast....but copies of them could be stored in a Faraday Cage. But I've NO CLUE as to the effect on the PV array.

Survival Blog had a Thread on this: http://www.survivalblog.com/2009/06/two_letters_re_protection_from.html

Basically the PV Array is at risk to be toasted at the junction level.  Some Survival Structure Builders include EMP Protected storage for reserved arrays to replace arrays exposed to EMP.


Offline phuttan

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Re: EMP effect on solar arrays??
« Reply #9 on: August 04, 2009, 05:06:39 PM »
I've researched EMP effects off and on during the past twenty-five year. My understanding is that any length of conductive material and any electronic equipment will be effected. Think of it as if it was a radio. If your antenna picks up a signal hundreds of time more powerful than your radio is designed to handle, your radio will be damaged. Electro Magnetic Pulse is every frequency in the electro magnetic spectrum, like a spark gap generator, but infinitely stronger. It induces high voltage in every inch of conductive material at the same time. It also has more than one phase. (fast, medium, slow) Combined, these effects can last for minutes. I read an article recently that quoted and linked to a recent government report. I haven't read the entire report yet. Also, Nuclear War Survival Skills is a good reference for most nuclear affects. The author worked at Oak Ridge Laboratories testing nuclear effects. I`ll look for the article and the author of the book.
Pat
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Offline phuttan

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Re: EMP effect on solar arrays??
« Reply #10 on: August 04, 2009, 07:24:17 PM »
Nuclear War Survival Skills was written by Cresson Kearney. There's a site that has the text on-line. I don't have the link and don't know how to post one. But there might be hope for them to survival. They used to say that all electronics within line of sight would be fried. But the new report says that many modern cars would survive because of shielding around vital components. So if your solar power components have shielding they may survive if not connected to your power system at the time. I'm going to finish reading the new report and will post anything I find.
Pat
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Offline Citizen Zero

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Re: EMP effect on solar arrays??
« Reply #11 on: August 04, 2009, 09:25:18 PM »
The government report that was released by the EMP Commission basically stated that a lot of the information circulating is not entirely true, this was backed up by actual testing in a simulated EMP environment. Their findings are both a good and bad thing.. The report is well worth a read. Unexpected things survived, while things that one would think would survive died..

Modern automobiles and other equipment actually has a rather good resilience to exposure to an EMP, most automobiles only suffered the need to be restarted. A small number of test vehicles suffered electronic malfunctions, but these were all minor. In all their testing I don't recall the report showing one vehicle that was actually rendered useless.

Here's a sample of the findings:

Bad:
Quote
SCADA systems are vulnerable to EMP insult. The large numbers and widespread reliance
on such systems by all of the Nation’s critical infrastructures represent a systemic
threat to their continued operation following an EMP event. Additionally, the necessity to
reboot, repair, or replace large numbers of geographically widely dispersed systems will
considerably impede the Nation’s recovery from such an assault.

Good:
Quote
Automobiles were subjected to EMP environments under both engine turned off and
engine turned on conditions. No effects were subsequently observed in those automobiles
that were not turned on during EMP exposure. The most serious effect observed on running
automobiles was that the motors in three cars stopped at field strengths of approximately
30 kV/m or above. In an actual EMP exposure, these vehicles would glide to a
stop and require the driver to restart them. Electronics in the dashboard of one automobile
were damaged and required repair. Other effects were relatively minor. Twenty-five
automobiles exhibited malfunctions that could be considered only a nuisance (e.g.,
blinking dashboard lights) and did not require driver intervention to correct. Eight of the
37 cars tested did not exhibit any anomalous response.

Bad:
Quote
Pulse-current injection and free-field illumination testing on a limited number of
refrigerators and freezers indicate that some units will fail from low to moderate EMP
levels. This testing indicates that substantial numbers of people would have to survive
without benefit of refrigerated foods for an extended period, until repairs or replacement
refrigerators and freezers could be obtained. Massive food spoilage at stores and
regional warehouses is implied.

Really Bad:
Quote
In a crisis, the priorities for emergency services are protection of lives, protection of
property, effective communication with the public, maintenance of an operational EOC,
effective communication among emergency workers, and rapid restoration of lost infrastructure
capabilities. An EMP attack will adversely affect emergency services’ ability to
accomplish these objectives in two distinct ways: by increasing the demand for services
and by decreasing the ability to deliver them.

Direct link to the report

Exec Summary: http://www.empcommission.org/docs/empc_exec_rpt.pdf
Full Report: http://www.empcommission.org/docs/A2473-EMP_Commission-7MB.pdf

As to the specific question on solar arrays, the satellite portion of the report is probably the most pertinent being that most are solar powered.

Edited for bad grammar..

As usual, just my $.02
« Last Edit: August 04, 2009, 09:27:47 PM by Citizen Zero »
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Goatdog62

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Re: EMP effect on solar arrays??
« Reply #12 on: August 05, 2009, 01:46:29 AM »
Great post CZ +1. Exactly what i was taught about EMP through DOE contacts.

Offline Steve W

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Re: EMP effect on solar arrays??
« Reply #13 on: August 05, 2009, 03:28:02 AM »
The government report that was released by the EMP Commission basically stated that a lot of the information circulating is not entirely true, this was backed up by actual testing in a simulated EMP environment. Their findings are both a good and bad thing.. The report is well worth a read. Unexpected things survived, while things that one would think would survive died..


As to the specific question on solar arrays, the satellite portion of the report is probably the most pertinent being that most are solar powered.

Thank you for the links!!

Just a note on space deployed solar panels, they use a type of cell composition not considered cost effective for widespread terrestrial use.  The incremental higher output, weight and durability advantages are useful in space, but costly.

To what level commercial grade terrestrial panels will differ from hardened space deployed panels?  Haven't found a good data source.

Thanks again!


Offline Steve W

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Re: EMP effect on solar arrays??
« Reply #14 on: August 05, 2009, 11:07:19 PM »
Does anyone have a clue as to the effect of an EMP pulse on a solar panel (PV array) ??  I imagine that the batteries in an off-grid system would survive. The charge controller and any inverter equipment would be toast....but copies of them could be stored in a Faraday Cage. But I've NO CLUE as to the effect on the PV array.

Just received an email announcing a large EMP conference in September:

http://www.empactamerica.net/

I've asked for more information and whether Solar Panels will be discussed.




Offline AtADeadRun

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Re: EMP effect on solar arrays??
« Reply #15 on: August 11, 2009, 06:45:08 PM »
Bear in mind that many of these effects are essentially dependent on length of conductor involved and fragility of the equipment in question.  A longer conductor will tend to have more current induced in it (hence the vulnerability, as it mentioned in the report, of long transmission lines to damage, including, you'll note, buried cables) and a larger conductor will have less resistance, allowing larger, potentially destructive, currents to flow.  That's probably why compressor motors, like refrigerator/freezers, took some damage in their testing:  in most houses, those are the strongest motors, which can be loosely correlated to the size of wire in the motor for a given voltage.  Most household devices that aren't connected to an antenna -- a widget whose sole purpose is to suck down radio-frequency energy -- will survive an EMP with no more damage than a possible need to restart it.

This isn't a high-probability event, either.  To get a wide-area EMP, like the "70% of US power infrastructure" the report discusses, you'd need to detonate a high-yield device in the upper atmosphere, which means needing not only a decent-sized nuclear weapon, but a reliable, high-payload missile with the legs to put the device in the ionosphere over the Eastern U.S.  That's an engineering feat *far* beyond anyone but France, the UK, the US, Russia, and China.  None of those (tinfoil hattery about the latter two notwithstanding) is at all likely to try and drop a nuke on us.  North Korea can't even get a medium-range Taepo Dong-2 off the pad and in the air for more than about two minutes before they auger in or blow up, much less toss a high-yield device another several thousand miles and have it go off in the upper atmosphere.

This report, while it makes some useful conclusions, has an agenda:  if a panel of distinguished folks whose job function is to figure out the threat of EMP attack on the US comes back and says, "Nope, this is pretty unlikely to happen on a nationwide scale, so let's just get some broad generic plans for local or small regional effects in case some bampot *does* actually set off a truck-nuke in downtown Peoria," they're going to look like fools to the people who paid for the study.

(edited to fix something stupid I said about motors)
« Last Edit: August 11, 2009, 07:05:49 PM by Atadeadrun »
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Offline phuttan

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Re: EMP effect on solar arrays??
« Reply #16 on: August 11, 2009, 10:52:32 PM »
The result in the EMP Report are interesting. With modern control units the damage wasn't uniform. One function doesn't work, another seems fine, and a third doesn't work until rebooted. And that's all on the same control unit or relay. They did say older low tech switches and control had better survivability.
After reading the report, I would expect that the damage wouldn't be to your entire array. Relays and controls are the most likely to be damaged. They also mention boxes controls are in don't provide grounded shielding. If you put your controls in metal boxes, wire in metal conduit, and ground everything, it should help.
Just my reading of some of the comments in the report.
Pat
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Offline AtADeadRun

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Re: EMP effect on solar arrays??
« Reply #17 on: August 12, 2009, 01:11:25 PM »
It occurs to me I didn't actually answer the original question, of the possible effect of EMP on PV arrays.  Likelihood is, the majority of the junctions wouldn't be harmed by a low-to-mid-power EMP on their own.  The most likely source of damage would be voltage induced in the line from your array to your charge controller/battery setup, and the way to prevent that is simply using a beefy power diode.  Every PV array/battery arrangement has one of these anyway, to keep the batteries from reverse powering and damaging the PV cells at night; it's like a check valve and only allows power to flow one way.

Power diodes are rated for forward current, reverse voltage and power (there are others, but for the simple application we're dealing with here, those are by far the most important).  Forward current is the amount of current the diode can safely handle, and power is the product of the voltage and current and is limited by the amount of heat the diode can safely dissipate.  Reverse voltage is the really important one here:  you want your diode to have as large a reverse voltage value as possible to prevent large voltages induced in the line between your PV array and charge controller/battery from damaging the array.  If you're really worried about EMP damage to your system, make sure the reverse recovery time, or trr rating, is in the nanosecond range, since the prompt effects of the first stage of a nuclear-weapon-induced EMP are that fast, according to the report mentioned earlier.  It wouldn't hurt, for this application, to have your diode have a high operating junction temperature, since the thing is going to, y'know, be in the sun getting hot all the time.  It'll lengthen the diode's life.

Poking around a few moments on digikey.com shows that a diode like that rated for 10A is likely to cost you between $5 and $10 apiece and probably have to be bought in a lot.  If you're just talking about a solar charger for a few AA's, I wouldn't worry about it much at all, but if you're really concerned about it, put it in something that'll act as a Faraday cage when you store it.
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Offline shangrily

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Re: EMP effect on solar arrays??
« Reply #18 on: August 12, 2009, 01:39:35 PM »
i thought a breaker box on your solar panels would protect them because an emp just charges the circuits and over loads them and a breaker box stops that????
im not an electrician but is there any way to test this???
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Re: EMP effect on solar arrays??
« Reply #19 on: August 12, 2009, 02:42:40 PM »
The problem, in this case, is that a breaker simply wouldn't be fast enough to overcome the nanosecond prompt effects of phase 1 of an EMP.  Those effects occur much, much, much faster than the millisecond response times of the purely mechanical systems of a breaker.  A breaker is far faster than merely human response times, true, but you're talking about the overvoltage/overcurrent sensor on the breaker needing to realize there's a problem, then actuate the opening mechanism, then the mechanism itself needs time to open the contacts far enough to quench the arc drawn between them.  Depending on amount of overcurrent and the age and settings of the breaker, you're talking a couple of milliseconds (for consumer and prosumer gear), which is millions of times slower than the nanosecond trr of a quality high-speed switching diode.
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Offline fasteddie

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Re: EMP effect on solar arrays??
« Reply #20 on: September 15, 2009, 04:53:01 PM »
does anybody know if solar panals sitting in my garage in there original shipping cartons would survive? also I just finished the book one second after and I thought it was fantastic to alert us how serios the threat is for this emp disaster (must read) for any prepper or survivolist. Ed

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Re: EMP effect on solar arrays??
« Reply #21 on: September 16, 2009, 03:03:49 PM »
There's no complete circuit if they're sitting boxed up, hence no place for current to flow, and therefore, no bad effects from an EMP.
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Offline outoforder2day

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Re: EMP effect on solar arrays??
« Reply #22 on: September 16, 2009, 05:29:05 PM »
First, I am by no means an expert. I've done some reasearch on this and have my own opinions just like everyone else. Take this for what it is: Free advice on the Internet.

Another method I came across in my research is putting the stuff in an old microwave oven (apparently, they have quite good shielding) and burying it a couple feet deep. This may seem extreme, but I'll bet it'd ABSOLUTELY work!!
The ground will do more than the microwave. A microwave is shielded in a narrow portion of the electro-magnetic spectrum. EMP is, by definition, a broadband discharge. Go ahead and put your cell in the micro (unplug the oven first!) and call it. See if it rings. It will. You need to attenuate a fast rising broadband spike to effectively deal with EMP.

If you shield your inverter/battery room with electrically joined and grounded copper sheeting and put Transient Protection Devices on all lines in and out of the room, your core equipment will survive. What is a Transient Protection Device? Well, a good one that actually acts fast enough is a Metal Oxide Varistor. They're cheap and easy to install in many types of lines. I'm not sure of the implications from a loss point of view on the solar panels, though. You'll probably loose some charging power.

On the Diode front, you'd need a fast acting Zenir Diode, I think. But... "The Zener diode has excellent response time but is unable to combine high power capabilities with low insertion loss". Low insertion loss is a big concern on PV arrays.

If you want a good overview of EMP from a scientific point of view, take a look at the ARRL magazine QST. QST did some extensive testing and there is a series of great writeups in the archives. Unfortunately it's members only. :-/

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Offline Orionblade

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Re: EMP effect on solar arrays??
« Reply #23 on: November 06, 2009, 11:55:38 AM »
I'll yank my research together on silicon carbide spark arrestors. *Scratches head*

I think that might be your ticket for a solar array protection kit. IIRC, they become highly conductive to high voltage spikes, but are nonconductive to line voltage. If nothing else, it would reduce the total power of the pulse arriving at the array itself, where normal electronic countermeasures could handle shunting the remaining energy.

Will report back over the weekend.
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