Electromagnetic pulse is said to detsroy electronics. Lightning is a type of EMP. As per my understanding lightning is basically a dielectric breakdown, it can be considered as DC current. Can it or any dielectric breakdown damage electronics from a distance, say 1m, 10 m , 100m or 1 km? If yes, how is that possible, because it cannot induce voltage in any wire as it is DC? Even if it is AC of few Hz, the length of any household wire will be very small as compared to the wavelength, then also there will be huge resistance to any volatge induced.
Can it or any dielectric breakdown damage electronics from a distance, say 1m, 10 m , 100m or 1 km? If yes, how is that possible
Yes. This is not an engineering answer, it is an empirical answer.
As a ham radio op, I had my station connected with antenna. In my beginning years, I never disconnected the antenna.
The station consisted of the antenna, and an HW-16 (Heathkit) with external power supply (also Heathkit). One day, there was a nearby lightning strike. Not direct, but within 500 feet (count of one second).
Later, I found that the "transmit" did not function anymore. I reached around the power supply to touch the HW-16, and got 800 volts in my arm.
Seems that the nearby strike raised enough EMF in the antenna, which traveled down the feed line, which traveled down the "ground" lead to the power supply, which traveled down the actual ground wire to ground. Burned out the rig to power supply ground lead.
I replaced the wire, and it worked fine.
But remember, the Heathkit HW-16 is an all tube rig. If it had any transistors, I don't know what would have happened. Just a little experience. So now I always disconnect the antenna when not operating. My friends say to ground the floating antenna too, but that would be too smart. 73, Joe W3TTT
The lightening can damage the facilities in two ways, by direct strikes or by electromagnetic waves.
Can the electromagnetic wave cause any damage ? yes, it's possible. The wave induces extra voltage across electronic components, if the components receive the right amount of voltage then you know what would happen.
Regarding your second question, the length of household wires are a way too small that's true, but the length of electrical networks across a continent can be big enough, for instance the electrical network between France, Belgium, Netherland, Germany, Austria and Czech, and they are all connected.
Another example is the phenomenon called 'coronal mass ejection', it's combination of materials and electromagnetic radiation, that caused some disturbances on the earth several years ago.
Further i refer you to this paper: https://digitalcommons.trinity.edu/cgi/viewcontent.cgi?article=1027&context=physics_faculty