If you read this post
https://www.electrical-contractor.net/ubb/Forum1/HTML/005239.html you know the company I work for has a large super market chain for a customer.
Here is another of their locations that had an outage.
I was not involved with this one, I don't know where I was while this was being repaired.
I am told the high voltage cut out did not open until the oil in the transformer was boiling and the primary's shorted.
Some of the guys on this repair got to see a security tape of the sparks blasting out of the pipe until the power failed.
Bob