I attended a national conference and trade show several years ago on this subject, mostly suppliers of EMP testing chambers looking for industrial and military buyers and I found there is an entire industry out there that deals with this kind of concern. What started the commercial test chamber business was not EMP concerns, but problems with early electronic ignition systems they were testing for cars back in the early 1970's, as many new vehicles would do strange things including sometimes their engines would stop if they drove near an airport and the rotating radar dish beam swept past. This started commercial testing to develop shielding methods for electronic systems for vehicles. Of course military testing was also being done to reduce military and aircraft electronic equipment failures when exposed to a high energy discharge in the atmosphere (EMP from a nuclear blast). EMP and solar flares basically have the same effect on electronics as the equipment being very near a lightning strike, same type of electromagnetic field spread across entire frequency range.
I talked to many of the real experts and described a typical solar pv system to see what could happen. I won't go into all the hard data and advice I received (some was classified at the time), but most felt since modules have internal wire paths between cells that can handle 10 to 15 amps of current, modules should not be damaged by EMP, solar flares, ect. However, being able to cause several amps of current to flow through any wiring or small electronic circuits is more than enough energy to fry tiny metallic foil wire paths on printed circuit boards, internal electrical paths inside micro-chips, ect. I also learned that even if you put an electronic device inside a metal enclosure, if you do not have special "wave guides", any wires that lead into this metal cage will just act like an antenna and carry the induced currents into the equipment. These "wave guides" and protective enclosures can be fabricated on site if you use materials that provide better shielding. Based on this research I would think most pv arrays with commercial grade modules will not have a problem, but look out for any electronic equipment, especially if it is left connected to external array and grid wiring during the highest potential for this energy to pass by. Power lines will act just like giant antennas for this energy field which will be "picked up" and carried through the wires to anything connected. The best advice I could offer a client several years ago who was really concerned was to purchase a backup duplicate inverter and charge controller, put them in a metal storage box having a metal to metal door with metal mesh gasket, and attach an earth ground. Short of being able to purchase military grade "hardened" equipment, I say a fair chance some inverters and charge controllers will be damaged, but the modules and batteries will not. Location, elevation, external grid connections, quality of equipment earth grounding, length and strength of energy discharge will all determine what is damaged and what is not. I am actually putting together an article right now related to this subject which is based on several boxes of research I have collected over the years on this subject, but remember, since everything today including a toaster usually requires some type of micro-chip to work, we may not have anything left to power even if our solar systems are not harmed!! Side note - I just rebuilt a 1977 Jeep CJ-5 which has a standard ignition system, manual toggle switches for all dashboard controls, has absolutely no electronic display or engine sensor devices, and now has an all fiberglass body - just in case I am wrong! Jeff Yago DTI Solar, Inc.
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