Most large stores have thier own transformer which they own. The need qualified maintenance guys to operate this stuff.
I recall one of the first "sky scraper" office towers in London had an 11Kv riser with 11Kv-415v transformers on each of the four plant levels in the building. ( basement. 1/3 up, 2/3 up and just below the roof )
Another had all the 11Kv(?)-415v transformers in the basement and massive bus bars vertically up the building, I recall being told these were square section copper 4 inch by 4 inch with braided expansion joints to allow for temperature changes.