Based on the short video, it appears to be a good-sized distribution step-down transformer burning in a substation. Rough guess, feeds 2000-10000 customers, but hard to gauge the size of it from the single video.
Further investigation into the substation - got it up on google maps - could be a transmission voltage transformer on fire. Definitely a transformer. They’re full of oil, used as a coolant and electrical insulation medium.
The transformer is trash, will cost a few million to replace. The how/why it happened - too soon to tell.
It’s a pretty big substation - looks to be 2 transmission level transformers, perhaps 230 kV to 138 kV +/- and also a distribution level substation stepping down to the voltage level typically seen along the side of the road (typically 4 kv to 26 kV depending on the system).
Would attribute to terrorism, myself.
Too small a foot print plus:
- the winter power debacle
- ramping into a warm spring and hot summer
- transformers built in China (lately).
If the transformer sat idle in the winter power outage and wasn’t tested for water content (condensation) at start-up, it could have been gassing right up until explosion.
on the big ones (345kV) up here in the north, we circulate the oil during cool down and check for water before re-start.
Or, drain and replace.
That and the Chinese thing; they ship them over fully assembled. If inferior equipment was used to save a buck...