Protection methodologies against HEMP and IEMI

HEMP (high-altitude [nuclear] electromagnetic pulse) and IEMI (intentional electromagnetic interference) are electromagnetic disturbances that couple into the power components, instrumentation and communications networks, with possible harmful effects.

These are events that are possible, even if not highly likely, and could cause temporary widespread blackouts, or at the extreme a permanently damaged system that takes days or longer to restore. If the cost of preventing or mitigating these effects is very high and the probability of occurence of the event very low, the protection may simply not be considered worthwhile. But it may instead be that relatively small costs of good practice in system design and component specification would make the system far less vulnerable.

More detail is given on the linked page about the project.