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Shortest Time length of mains brownout or blackout?

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Advanced Member level 5
Jun 13, 2021
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It's not time, it's voltage level. A brownout is a drop in voltage-10%-15%. A blackout is a complete loss of voltage.

Maybe if you read the article that you posted, you'd know that.

If you really need to know the shortest time, it's 1 atto-second.

The number is bafflingly small. The largest possible value this fundamental unit of time could be is one thousandth of a quectosecond, according to research published last month in the journal Physical Review Letters. That’s ten to the -33rd power or, as Live Science helpfully put it, just one millionth of a billionth of a billionth of a billionth of a second.

* I'm pretty sure it was a brief blackout/brownout that once caused my computer to turn off. So brief I don't think the lights flickered. I turned the computer back on and the problem did not recur.

* I built a house voltage monitor. I added a blackout alarm so it could detect a sudden drop in amplitude. With effort I got it to beep if it dropped for just a few mains AC cycles. It has done so a few times for occasional brief blackout/brownout even though it wasn't noticeable to me.


Many years ago there was this fast interrupting 20kV switch for power distribution.
If I remember right, then this caused a power off time of 100ms.

It was used when a tree touched the high voltage lines and caused a continous lighnting along it's branches. With the 100ms gap the "fire" should extinguished.


Are you asking for a definition of "blackout" and "brownout" or expectable time range of mains voltage excursions?

In the latter case, there's obviously no minimal time. Mains voltage dips and short interruptions can have any duration. Some typical cases are covered by EMC tests according to IEC 61000-4-7.

dip to 0 % for 1/2 cycle
dip to 0 % for 1 cycle
dip to 70% for 0.5 s
short interruption 0% during 5 s

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