Electronics > Power/Renewable Energy/EV's

Solar Electric Panels vs Lightning EMP

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SeanB:
Not necessarily Guy, they just would have had to have been at the node of the EMP wave, which would have concentrated the energy nicely.  Initial pulse creates a sharp wave, which reflects from nearby things like the metal edges, roof struts, nearby poles and terrrain, and this reflection arrives as the next return pulse is travelling up the leader, and this mixing then makes areas of high potential and areas of low potential. Thus the lines curving alond, they follow a path of intersection of 2 or more curved reflections to make a standing wave pattern on the panels.

BTW how is your postal test coming along?

System Error Message:
so how much damage does lightning cause to solar panels? Did you test whether or not it still produces the same amount of electricity? In tropical countries you get sun all year round but with bad storms.

Red Squirrel:
I wonder if some kind of grid/mesh over the panels could help, or if the energy is simply too great.  Something like what they'd use for a dog cage.  Of course you'd want it to be grounded.     You would lose a bit of performance from the panels though.     As for panels being grounded I was talking about the string.  Ex: you have a string of 4 panels, would the negative side be earth grounded with the rest of the electrical system?  Or are they normally floating?  Wonder what is better?

bitslice:

--- Quote from: TerraHertz on May 10, 2016, 12:58:28 am ---
A question: has anyone broken open a large (190W) solar panel, and examined the internal construction? With these panels, looking through the glass it _looks_ like the cells are simply sitting in a cavity between the front glass and rear backing sheet. But the arc-tracing photos look like there's actually a very clear filler material.

--- End quote ---

Optically clear silicone is used
http://www.dowcorning.com/content/discover/discovershowcase/solar.aspx

It's really quite expensive too.

jnissen:

--- Quote from: TerraHertz on May 13, 2016, 01:20:32 pm ---
--- Quote from: Red Squirrel on May 12, 2016, 11:30:20 pm ---Is the ground of a solar panel install typically bonded to earth ground?  I would imagine a lot of the energy just got shunted straight to ground, although that's still way more voltage that the cells are rated for so it is quite impressive they survived.  Wonder what is the best defence against this, a ground tower on the property perhaps?  Also want it in a spot that it won't cast a shadow on the panels.

--- End quote ---

Individual panels don't have a 'ground'. They have plus and neg leads, which on roof installations are typically wired in series over however many panels there are. What happens in typical inverters with the leads coming down from the roof panels I don't know.

But it's important to realize that these panels were not actually struck by lightning. All that visible tracking on the panels was caused by a very fast risetime E-field pulse radiating from the nearby lightning strike. The field orientation was vertical (as you'd expect) hence all the tracings run pretty close to vertical on the panels.
So what was happening was charge carriers (electrons most likely) that were present on the cell surface were being pulled vertically along the surface. So fast that the metal (silver) conductor strips right beside the arc traces had almost no effect on the trace paths.

I still have to do some drawings of the panel series layout, relative to the field orientation. The diodes and all the inter-cell wiring would have played no part in the cell tracing, but would see sharp HV current pulses 'a while' (nanoseconds) later. Still enough to destroy most of the diodes.

It's a pity I have no way of knowing what order the panels were wired. I'd guess the ones with no damage were furthest from the strike.

--- End quote ---


Panel frames and such should all be electrically grounded to earth ground. This is a requirement here in central Texas. Each panel must be wired into a solid copper grounding wire. In my case a single large gauge bare copper wire is used for multiple panels. They sell special clamp screws that cut through the frame anodizing and accept the ground wire.

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