Author Topic: EMP...Faraday cage on solar panels?  (Read 14256 times)

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joestue

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Re: EMP...Faraday cage on solar panels?
« Reply #27 on: June 20, 2016, 09:43:15 AM »
The volts per kilometer produced by natural events is proportional to the area of the loop passing through the earths magnetic field. you need on the order of 100,000 square meters of area to get a dozen volts.

The problem for the grid is the current produced in the line is enough to cause a few hundred amps of dc current to flow, saturating the transformer core which then draws excessive ac amps from the line. The only reason the current can flow is because the neutral grounded at both ends. all they have to do is lift the ground at one end, put a capacitor in series. There could still be net dc show up from one phase to another, but usually the phases are alternated with each other so each has the same inductance to ground, so it would be very minimal dc if any significant current.

a congressionally funded study iirc estimated it would cost 50,000 dollars for each of the 1000 largest substations to open the loop with a capacitor, resistor and spark gap, why the utilities haven't installed this equipment themselves, i don't know. they have known about this problem for nearly 100 years

jlsoaz

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Re: EMP...Faraday cage on solar panels?
« Reply #28 on: June 22, 2016, 09:04:23 PM »
The volts per kilometer produced by natural events is proportional to the area of the loop passing through the earths magnetic field. you need on the order of 100,000 square meters of area to get a dozen volts.

The problem for the grid is the current produced in the line is enough to cause a few hundred amps of dc current to flow, saturating the transformer core which then draws excessive ac amps from the line. The only reason the current can flow is because the neutral grounded at both ends. all they have to do is lift the ground at one end, put a capacitor in series. There could still be net dc show up from one phase to another, but usually the phases are alternated with each other so each has the same inductance to ground, so it would be very minimal dc if any significant current.

a congressionally funded study iirc estimated it would cost 50,000 dollars for each of the 1000 largest substations to open the loop with a capacitor, resistor and spark gap, why the utilities haven't installed this equipment themselves, i don't know. they have known about this problem for nearly 100 years

Thanks, you seem to be saying that on the scale of a home solar setup, it's maybe not worth focusing on, but is still worth focusing on for the grid.  While I'm not super-focused on preparing for this, I do think if I can find a moderate prudent solution, I'd like to prepare it. 

A couple of years ago I had to build a fence around my panels to reduce theft risk (they are on my front lawn).  I'm wondering now if some sort of "top" could be built to this fence and produce a primitive metal cage of sorts that I could deploy only if there was warning of a significant solar event.  Still, not sure this would protect my inverter, which is inside.  In fact, I understand so little of Faraday cages that probably the whole idea is just off and very unlikely to have any effect of protecting my system.

joestue

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Re: EMP...Faraday cage on solar panels?
« Reply #29 on: June 22, 2016, 10:32:29 PM »
A faraday cage works in theory, but in practicality the cage has a resistance R. whatever current induced in the cage causes volts across it, which radiates it inside the cage.

The loop area available in any average system is too small (it can be made almost zero) to induce any significant voltages, and its utterly hopeless to try and protect your system from the emp available from a nuke.

It is not impossible to harden your system against a direct lightning strike, but to do so will require more money spent in copper than the system is worth. it would be cheaper just to have a duplicate system buried in steel trashcans, 5 feet deep in the ground (such protection would also survive the emp from a nuke)


if you want to experiment with this, run a three wire loops in the X, Y and Z axis. say one loop is 5 feet by 50 feet N-S, the other 5 by 50 feet in the E-W axis, and the other is laying flat on the ground.

I have no idea what voltages you'd expect to get from such a system. a chopper stabilized opamp will reliably amplify micro volts by a factor of 1000 and you should be able to datalog the readings. who knows.. but you'd be dealing with micro volts and maybe millivolts.. until lighting strikes nearby.. then its millions.

dnix71

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Re: EMP...Faraday cage on solar panels?
« Reply #30 on: June 23, 2016, 07:20:43 PM »
The flash from a nuclear explosion would fry your panels anyway. I have seen thunderstorm lightning so bright it caused my panels to turn the MPPT on in the middle of the night.

When the grid fails the world will return to the days of Fred Flintstone and Barney Rubble.

thirteen

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Re: EMP...Faraday cage on solar panels?
« Reply #31 on: June 23, 2016, 10:30:39 PM »
Would solar panels be trashed if not in use. Say stored in a basement or tunnel? How long would the blast last. Would we have any warning? Just wondering. 13
MntMnROY 13

joestue

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Re: EMP...Faraday cage on solar panels?
« Reply #32 on: June 24, 2016, 12:48:27 AM »
for the light/radiation to damage the panel you'd have to be within the blast range. ie.. dead.

Mary B

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Re: EMP...Faraday cage on solar panels?
« Reply #33 on: June 24, 2016, 02:25:30 PM »
I have read reports that said solar panels would likely survive an emp if they have proper lightning protection devices on the output of the string to clamp maximum voltages. Look for a device with the fastest response time. They might be degraded a bit but still function. Your charge controller and inverter are far more likely to be fried.

Johann

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Re: EMP...Faraday cage on solar panels?
« Reply #34 on: June 26, 2016, 05:27:12 PM »
Here is my thought.
If any emp is strong enough to damage your panels you have major problems.
In an event it would happen, what are you going to power afterwards ?
Most of the things would be damaged, like electronics.  You might be lucky if a incandescent bulb still works.
Do you really think that you get advance notice to pack all your electronics/electrical stuff into a metal box?

When you see politicians run like roaches then you will know that it is time to pack.

MattM

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Re: EMP...Faraday cage on solar panels?
« Reply #35 on: June 26, 2016, 08:57:45 PM »
I cannot find any reason solar panels would be vulnerable to EMP if they have something like a battery bank directly tied in to flatten out their voltage.  Might be an issue on microinverters, but shouldn't on anything with over-voltage protection.

Mary B

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Re: EMP...Faraday cage on solar panels?
« Reply #36 on: June 27, 2016, 03:15:28 PM »
I suspect it will punch holes in the silicon wafer and degrade it some, how much is unknown. I run a lightning protector in the panel junction box that clamps at 500 volts. 10 nanosecond clamp time to deflect 10,000 amps, 25 nanosecond for 50,000 amps! Delta LA302 DC is the part number and they are relatively cheap!

Johann

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Re: EMP...Faraday cage on solar panels?
« Reply #37 on: June 27, 2016, 04:38:47 PM »
I cannot find any reason solar panels would be vulnerable to EMP if they have something like a battery bank directly tied in to flatten out their voltage.  Might be an issue on microinverters, but shouldn't on anything with over-voltage protection.

It is known that there is a very good possibility the electrical power or phone line will be destroyed and the US proved it in the 60's when they knocked out part of Hawaii and Australia while they performed a small test 800 miles away in the middle of the ocean. If your assumption would be right, the power lines/net should be ok since you have millions of folks connected to it which is a very big load.
Just look at a solar panel. you will see a lot of arcing when a solar panel get's hit with thousands of volts that will burn all the tiny electrical lines up at the cells and between the cells since the high voltage is looking for the shortest way and now add the high amps on top of that that will help to continue a big arc.
Just throw a cell in the microwave and run it, nice fire works will flare up.

Between the solar panel and batteries is a thing that is called a charge controller. That will burn up within microseconds and the batteries are now disconnected from the panels and there could be no load present to the panels.

Remember that a solar panel is still a electronic device.

joestue

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Re: EMP...Faraday cage on solar panels?
« Reply #38 on: June 27, 2016, 06:19:10 PM »
the rise time for the emp surge is on the order of 10nS, you can read all about this stuff if you want to, i've forgotten most of it.

anyhow, short answer is, anything longer than a few feet will have 10,000 volts on it.

Thats why the emp test that the Russians did, one of the last open air tests; the 3 foot buried telephone wire was fused. as in: vaporized. along with the gas discharge lightning protection every few kilometers.

richhagen

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Re: EMP...Faraday cage on solar panels?
« Reply #39 on: August 04, 2016, 03:43:21 PM »
I had a panel which I think was damaged by a nearby lightning strike.  Never worried too much about protecting the panels from an emp, because located near downtown Chicago, I don't think the roof they are on would survive that much longer.  I would guess it might be easier and possibly cheaper to have a spare set of panels and a spare controller set aside in a well grounded bunker of some type, especially if the physical structure that your current panels are on would not likely survive, but that depends on your location and the accuracy of someone else's equipment.  I don't think I could dig a hole deep enough to survive a war where I am at.   Rich
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Ungrounded Lightning Rod

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Re: EMP...Faraday cage on solar panels?
« Reply #40 on: August 04, 2016, 07:21:55 PM »
IIRC:

... Solar flares give V/km (volts per kilometre) induced voltages. ...

Thus I'd have thought that PV wouldn't even notice, but decent bypass and blocking diodes would ensure that any small voltages and currents induced would be likely dissipated safely.

Bingo!

Solar flares are a problem for power grids because the lines are many kilometres long.  The induced voltage from the (slowly) moving mag field adds up over long distances to hysterical levels.

Your panels are small by comparison to the wavelengths involved and won't pick up any substantial voltage.  Your wiring from the panels to the inverter may be long enough to pick up a few volts.  But even if they pick up a couple hundred it's nothing compared to a surge from a nearby lightning strike.

The main problem with long distance power lines is that, if the central Y point of a three-phase transmission line's transformers are grounded at BOTH ends, a bad mag storm can induce enough common-mode current that it combines with the line current to saturate a transformer core at one peak of the current waveform.  Then the inductance drops by maybe something over five orders of magnitude.  Without the inductance to impede it, the current from the transmitted power climbs by a similar factor (and the unbalanced current may also lead to saturation of the other transformers in the group at both ends of the line).  The heating of the coils goes up with the square of the current (TEN orders of magnitude, YIKE!) and the power from the grid fries the transformers almost instantly.  Then the line is out until a half-dozen house-sized transformers are manufactured, shipped, and hooked up.  With a large number of lines suffering the problem simultaneously it could take a year or more to bring the whole grid back up.

But that's a problem for long high-tension lines blowing up giant transformers in the substation.  And if you're out in the country and your utility hooks up your "pole pig" transformers in Y rather than delta, you might just possibly have problems with the pole pigs that feeds your house, too, before the grid protects them by going down.  But it's not an issue for the wiring from your panels to your inverter.  (Even if your panels are on the hill behind your house rather than on it or beside it, and you also risked galvanic corrosion and lightning surge problems by grounding one of the feed wires from your panels at the panel end.)

For the grid the solution is to put a resistor in the grounding of the center of the Y on at least one end.  But for the grid such a resistor is a big box, comparable in size to the transformers, very pricey and requiring maintenance.  (I think they're actually full of water with electrodes it it...)  And it only protects them from trouble every few decades and from disasters every couple centuries.  So there haven't been many installed, and a lot of long lines are still unprotected.

Early telegraphs used the ground for one of the wires, and (as I understand it) were in place for the last giant magnetic storm.  So there actually was an event with some damage back then - though it wasn't understood at the time.

Rural POTS telephones, with many miles of wire and a ringer circuit for party lines that does a return through ground, may have similar issues.  (If the line is long enough that the voltage gets up to 80V or so, some party line bells might do a little oddball ringing - much like they do in severe electrical storms.  B-) )  The old copper T1 (twisted pair) and T3 (coaxial) long distance cabling might also have had trouble.  But it's pretty much all been replaced by fiber, which is immune, (and the copper sold off to pay for the fiber installation B-) ).

Edit:  Posted all that before I saw that there was a second page where it was all answered already.  Leaving it up just for the hell of it.
« Last Edit: August 04, 2016, 07:26:55 PM by Ungrounded Lightning Rod »

jlsoaz

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Re: EMP...Faraday cage on solar panels?
« Reply #41 on: August 10, 2016, 10:02:46 AM »
Edit:  Posted all that before I saw that there was a second page where it was all answered already.  Leaving it up just for the hell of it.
Last Edit: August 04, 2016, 07:26:55 PM by Ungrounded Lightning Rod

From my side, thanks for the various informative responses, this makes some more sense.  I have to admit I'm still concerned, including for my related equipment (inverters, charge controllers, etc.), and including if there could be ancillary aspects that could damage them (such as if the flare itself did not damage them, but there was some sort of problem with the grid very close to my house).  However, at this point the concern is somewhat reduced.

joestue

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Re: EMP...Faraday cage on solar panels?
« Reply #42 on: August 10, 2016, 08:22:59 PM »
Quote from: Ungrounded Lightning Rod

For the grid the solution is to put a resistor in the grounding of the center of the Y on at least one end.  But for the grid such a resistor is a big box, comparable in size to the transformers, very pricey and requiring maintenance.  (I think they're actually full of water with electrodes it it...)

This is ridiculous who told you that? Congress spent money investigating the matter and they estimated 50k per transformer for a spark gap, capacitor and resistor. The resistor only passes dc current after the storm shows up,[10vdc per mile maximum] the capacitor is the most expensive part because it has to pass the unbalanced 60HZ component, and higher harmonics, and it has to be rated to handle the DC voltage. All this is explained in great detail already.


So far it seems the only difficulty is the installation, and the potential transformers in the substations may have to have their grounds lifted and reconnected to the transformer, not ground. And there are other monitoring systems that will have to handle the residual dc components


Also the lifting of the ground will increase the efficiency of the transformer slightly because there is residual dc always present on long transmission lines. So eventually the capacitor will pay for itself.

liberty_911

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Re: EMP...Faraday cage on solar panels?
« Reply #43 on: October 05, 2016, 09:51:55 AM »
To answer the original question, I've been told by a PhD in physics that the panels would survive an EMP, but that the diodes that are inside the panels would possibly be destroyed. Hence, buy some spare diodes as back up.  However, the rest of your equipment would be fried; any charge controllers, inverters, etc... You need to have a spare electronic equipment (as well as diagnostic equipment) stored in a Faraday cage.

jlsoaz

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Re: EMP...Faraday cage on solar panels?
« Reply #44 on: December 28, 2016, 12:03:17 AM »
To answer the original question, I've been told by a PhD in physics that the panels would survive an EMP, but that the diodes that are inside the panels would possibly be destroyed. Hence, buy some spare diodes as back up.  However, the rest of your equipment would be fried; any charge controllers, inverters, etc... You need to have a spare electronic equipment (as well as diagnostic equipment) stored in a Faraday cage.

Ok, thanks for this additional answer.  As I consider the matter, if I really wanted to be super-prepared, it does perhaps make some sense to have a modest-sized cage inside of which is some key electronic equipment.

In my own case, there's no way that I'm handy enough to deal with everything that would be fried in a worst-case scenario, but I'll have to think it through a bit.

Ungrounded Lightning Rod

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Re: EMP...Faraday cage on solar panels?
« Reply #45 on: January 03, 2017, 01:32:09 PM »
Quote from: Ungrounded Lightning Rod

For the grid the solution is to put a resistor in the grounding of the center of the Y on at least one end.  But for the grid such a resistor is a big box, comparable in size to the transformers, very pricey and requiring maintenance.  (I think they're actually full of water with electrodes it it...)

This is ridiculous who told you that? Congress spent money investigating the matter and they estimated 50k per transformer for a spark gap, capacitor and resistor. The resistor only passes dc current after the storm shows up,[10vdc per mile maximum] the capacitor is the most expensive part because it has to pass the unbalanced 60HZ component, and higher harmonics, and it has to be rated to handle the DC voltage. All this is explained in great detail already.

That was my impression from an article I read a long time ago, when this issue first came up.  I presume I misinterpreted what was said.  Thank you for your more informed correction.

Mary B

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Re: EMP...Faraday cage on solar panels?
« Reply #46 on: January 03, 2017, 05:26:18 PM »
Key to emp protection is EVERY wire entering the cage has to come in through a surge protector capable of very high speed clamping to ground to protect the contents, 5 nanoseconds or less clamp time. And that protection comes with a STEEP price tag! http://www.transtector.com/products/emp-emi-protection/e3pm A 17 volt 30 amp DC protector is $400!

joestue

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Re: EMP...Faraday cage on solar panels?
« Reply #47 on: January 03, 2017, 07:49:53 PM »
You can buy neutron detectors that will give you a few microseconds early warning. Said early warning can let you use garden variety mosfets to short out the wires going into your "black box"  They are a few hundred dollars and export controlled last I heard.

Mary B

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Re: EMP...Faraday cage on solar panels?
« Reply #48 on: January 04, 2017, 03:20:52 PM »
Can you design the circuit to act in 5ms or less? And will that mosfet hold up to hundreds of amps surge?

joestue

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Re: EMP...Faraday cage on solar panels?
« Reply #49 on: January 04, 2017, 06:03:16 PM »
my guess is those detectors would be wired up to a pre-ionizer hv circuits to protect the front end of radios and radar type circuitry with gas tubes.

20uS is a long time, and how many amps the emp will actually deliver depend on how close to the bomb you are. so, you do what you can afford to do..

Ungrounded Lightning Rod

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Re: EMP...Faraday cage on solar panels?
« Reply #50 on: January 04, 2017, 08:48:41 PM »
20uS is a long time, and how many amps the emp will actually deliver depend on how close to the bomb you are. so, you do what you can afford to do..

Though there's no point in doing more than enough to protect your gear unless it's close enough to ground zero that it doesn't really matter.  B-b

Mary B

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Re: EMP...Faraday cage on solar panels?
« Reply #51 on: January 05, 2017, 04:35:30 PM »
Commonly used RF surge protector, 7ns turn on time http://www.polyphaser.com/products/rf-surge-protection/is-b50hn-c0 I have a bunch of Polyphaser stuff in my station... They are affordable and fast enough to protect the radios from all but worst case(being in the worst path for EMP).

Gordy

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Re: EMP...Faraday cage on solar panels?
« Reply #52 on: February 07, 2017, 10:50:26 PM »
 I have learned that these groups are NOT the best place to learn about EMP protection, it's just to hard to figure out who is right and who has been mislead with false info. Sol-Ark EMP Solar generator, https://www.youtube.com/watch?v=r1qJoxDvzOo talks about their system. they don't tell everything, but do mention chokes on every wire going into their system, and other things they don't specify. Two week's ago I talked with my nephew and his buddies who served in Iraq and Afghanistan. They said the Army uses steel shipping containers with a fire proof insulation on the inside, then a wire screen and more fire proof insulation. The container was grounded by being placed on wet ground, No grounding rod which would act as an antenia. The  wire screen was supplied with 3 to 6 volt DC running through it to ground. The reason for the fire proof insulation is that the screen will glow red hot as it catches the RF pulses. They said that there would be at least 3 pulses from a high altitude nuke generated EMP. First would be a magnetic pulse, then several RF pulses. It was also their opinion that if it happens it will be high altitude nukes, as not to contaminate the country for invasion purposes, Unless it is a MAD (Mutual Assured Destruction) situation.

joestue

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Re: EMP...Faraday cage on solar panels?
« Reply #53 on: February 08, 2017, 02:18:50 PM »
There isnt enough energy available to make a mesh glow red hot from the emp pulse, not to mention its the second layer. ( the outer one would be vaporized...)

More likely the second layer of mesh is to provide the required db isolation (and redundancy) so they can continue to run their systems uninterrupted.

Another possibility is the directed energy weapons currently being made can produce a stronger emp than a nuke can, and their higher frequencies require better shielding.



But as far as emp energy, the E1 pulse is up to about 6-7 megawatts per square meter, but the power rises from 0 to 100% and back down to 50% in the first 100nS, and its over by 1000ns. So maybe 1-10 joules per square meter. This is worst case senario at 50KV/m.

edit: I made that part Bold
current unclassified information on explosive pumped flux compressors feeding virtual cathode magnetrons is 20 years old as far as i know.
« Last Edit: February 08, 2017, 08:40:29 PM by joestue »