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).
Knowledge and sheet right here! THIS is why I’ve stuck with FR all these years.
My favorite transformerfag!
#RobotsInDisguise