A powerful thunderstorm rolled through my area yesterday and something happened that I had never noticed before. Many times before when powerful thunderstorms with lightning rolled through, the AC mains power has either not been affected or went totally out after a nearby strike. Yesterday something different happened...

After a very bright and loud (and most likely nearby lightning strike, but not sure where it could have hit), the AC mains dropped out (to zero I guess) and stayed out for about 5 seconds then came back ON.... What could have caused this? I am fairly certain there are no grid substations too nearby where I live. Furthermore, I guess to answer this question, we have to assume that my small city uses the most common or "default" type/method of electrical power distribution.


The circuit breakers used in power distribution often have a feature called a "recloser", which will make some number of automatic attempts to reclose the breaker after a fault, in order to deal with transient problems such as nearby lightning strikes.

In this case, the strike didn't cause a permanent short circuit, so the recloser was successful on its first attempt.

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    \$\begingroup\$ I think you answered correctly, but some addition is necessary. Reclosing systems can perform their tasks multiple times. The first shot is after very small period of time, about 100-300 ms. Then, if there is a short-circuit, it disconnects, and after another time (several seconds) tries again. The longer time is required for the switchgear to prepare its motors for another opening. I think that the OP just didn't notice the first reclose and this was the second attempt (however they could have set the device for 5 seconds in the first reclose dead time) \$\endgroup\$ – Voitcus Aug 21 '15 at 9:16

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