[ethbr1]

> medium caliber semi-automatic rifle

Technically, anything that can put a hole in an oil-filled transformer. https://en.m.wikipedia.org/wiki/Transformer_types#Liquid-coo...

You don't need to break it... just crack the radiator enough for all the circulating fluid to drain, then it overheats.

[EdJiang]

Important to point out this isn't just theory, it's actually happened (in the SF Bay Area!) with a regular rifle.

https://en.wikipedia.org/wiki/Metcalf_sniper_attack

https://www.npr.org/sections/thetwo-way/2014/02/05/272015606...

[ethbr1]

Also in the north GA mountains in the 1970s.

[applied_heat]

Any transformer over about 5 MVA will probably be equipped with a low oil level switch that de-energizes it

[jpc0]

If all you wantes was to kill the power I don't see the difference...

Sure the repair is easier/quicker but the economic damage was already done...

[applied_heat]

The lead time on a transformer that size is probably a year, so a year long outage has a lot more damage than a 2 week outage

[lll-o-lll]

Would the switch on the transformer possibly be software controlled? (By software, I am wondering about firmware on a device reading a sensor, as opposed to a physical mechanism). I don’t know enough about the internals of these things, but I wonder if you could maliciously overwrite firmware, whether certain protections could be made to fail.

I’m going to assume this kind of thing is likely covered in FMEA and such, so is unlikely.

[idiotsecant]

It would be an input to a relay protection system which is technically software controlled most of the time but quite secure.