So, power line transformers: During Hurricane Sandy, I and many others saw them exploding like fireworks in our neighborhoods – even in urban areas where there were non of those demonized ‘trees’ attacking them. Apparently, they’re some sort of house-of-cards bomb-like device with most of them having a centuries-old circuit breakers tech that essentially don’t work fast enough. So, when they get a power surge, they heat up tremendously exploding the mineral oil they’re packed in (which doubles as a non-conductive heat sink and cyan-colored firework combustible material). Then the next transformer in the line is overloaded and explodes. And soon enough, continental stone-agism ensues.
Is that what happened During Sandy? Is the info from sites such as Popular Mechanics correct? If we invested in a stimulus package to update the infrastructure three years ago, could the massive blackouts have been avoided?
I find it hard to believe that a overload or short for a few milliseconds can make a transformer simply blow up because a HUGE amount of power has to be dissipated for it to heat up that fast (for example, a kilogram of iron requires about 450 joules to heat it up by 1C, say 200C to reach the boiling point of the oil, which requires 90 kW for one second, and that is only the loss in the transformer, so say at least 900 kW for 1 second, or 900 MW for 1 millisecond). This is also based on my experience with small AC transformers, which can handle a total short for at least seconds before overheating. Unless there isn’t any kind of overload protection like a fuse or circuit breaker, but even that shouldn’t cause instantaneous failure (witness this exploding substation, which explodes when the transformer ruptures and sprays vaporized oil on the arc due to another fault, which overloads it, some minutes(?) after it occurred).
The only time I have ever seen such instantaneous failure is in a switchmode power supply without over-current protection, and it was the switching transistor that blew up, not the transformer.