Available EMP protection devices?
Solution 1:
Certainly having your equipment on surge-protected power supplies, ideally UPSs, makes some sense for this scenario but the only way to add significant EM protection would be by placing your hardware inside a well grounded Faraday cage of some sort. I'm not aware of any commercially available products in this area and obviously the size of installation would be key to the resources needed to carry out this work but I do know that given the time and money it would be possible to build an entire data centre inside an effective Faraday cage if you so desired.
Solution 2:
The surge generated by a solar event is generally caused by swift oscillations in Earth's magnetic field which in turn induces current in long conductors. In extreme cases (I think that 1980's era X-class solar flare that blacked out a lot of Canada was one) the magnetic fields from the CME itself reach the ground for big-big fun; we haven't yet had a flare that size in the Internet era.
This means there are two surges you have to defend against:
- The indirect-effect surge coming down your mains feed thanks to those long transmission lines acting as antenna for the magnetic fields.
- The direct-effect induced current in your own electrical plant.
The first type can be handled by Ye Olde Surge Suppressors, or if you want to get fancy with it a line conditioner will do the job better.
The second type is a lot harder to defend against. Happily, you're not likely to be vulnerable to it since it requires long, straight runs of conductor. Long twisted-pair runs may get higher incidents of bad signals on the wire but shouldn't induce enough voltage to smoke equipment. Long power runs may pick up dirtier power than normal, so equipment sensitive to such small voltage changes may act badly.
A Farraday Cage does offer some protection, so long as it doesn't share a ground with the powered equipment inside.