The March 6th photo showed an empty pad adjacent to the superchargers and switchgear. This is probably awaiting a transformer for the superchargers, and the other transformer onsite is for the WaWa itself. With the remaining conduit onsite, it's also possible they need still need to run a secondary feed from the transformer onsite to the empty pad for the supercharger transformer. Just guessing here from the photos.
If someone stops by, it would be interesting to get some additional photos or info describing the relationship from the supercharger equipment and empty pad to the other transformer that was/is fenced off.