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.
11
-
$\begingroup$ does a dc current cause a magnetic field? and the collapse of that can cause a magnetic field in another conductor? $\endgroup$– Solar MikeSep 1, 2018 at 15:35
-
$\begingroup$ @SolarMike It's difficult to understand the tone online, are you trying to guid the OP to find the answer by asking the question or you actually asking if the dc current cause a magnetic field ? $\endgroup$– user14407Sep 1, 2018 at 19:34
-
$\begingroup$ @SamFarjamirad well, take an intelligent guess... $\endgroup$– Solar MikeSep 1, 2018 at 20:28
-
$\begingroup$ @SamFarjamirad How about considering the possibility that I was leading the OP to find out the answer for themselves. $\endgroup$– Solar MikeSep 1, 2018 at 20:30
-
1$\begingroup$ @SamFarjamirad, airbag deployment caused by power transmission lines is quite a different thing from a possible EMP caused by lightening. The former was caused by AC interference from the power lines, which are basically very long antennas and is why most high-voltage transmission lines are now DC (radiation loss). Planes get hit by lightening all the time; I even saw the aftermath of an F4 radome being struck by lightening. Nothing happens to airplanes when they get hit by lightening. $\endgroup$– BillDOeSep 2, 2018 at 20:40
|
Show 6 more comments
2 Answers
$\begingroup$
$\endgroup$
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
$\begingroup$
$\endgroup$
4
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
-
$\begingroup$ if induction is possible, then it means that lighteniing is not dc but ac. is that true? if yes, what is the frequency or range of frequency? $\endgroup$– edsxcdSep 2, 2018 at 12:17
-
$\begingroup$ @wdcxsd lightening can't be AC, why ? Because it happens when electrons moving towards higher potential, if it's AC then it means they tend to swing back and forth or they tend to move back to lower potential again! Obvious contradiction. DC current can also induce a secondary current in a closed loop. DC is direct current but it can vary with time, it can increase or decrease but it is still DC. $\endgroup$– user14407Sep 2, 2018 at 12:24
-
$\begingroup$ so u r saying that in lightning , current changes amplitude but not direction, hence it is dc but yet capable of electromagnetic induction. am i infering correctly? $\endgroup$– edsxcdSep 2, 2018 at 12:33
-
$\begingroup$ @wdcxsd One way to generate the EM is oscillation, the general principal says any acceleration of electron or charged particle cause EM radiation, obviously electrons accelerating during lightening. I don't want to make any assumptions but i recommend you to read or review once more the very basics of electromagnetism, 'University physics Young and Freedman' is a very good starting point if your are an absolute beginner, but it takes a lots of commitment to read it. $\endgroup$– user14407Sep 2, 2018 at 12:41