1) Direct Utility Voltage i.e. 13000V to 240V or 208 V?
Or 2) Direct Utility Voltage i.e. 13000 to 480V and then Step Down From 480 to 240 or 208V?
Thank you.
DISCLAIMER OF LIABILITY: OPINIONS GIVEN HERE BY ME IN NO WAY ARE TO BE CONSTRUED AS ENGINEERED DESIGN GUIDELINES!
I'm very serious about that as I *am* an EE and that carries liability in this case. I AM NOT a state-registered PE (Professional Engineer) and building electrical design is certainly not my profession.
That said...
It sounds very much like you are actually are going to do a large power installation. If this is not just idle 'why' speculation then YOU MUST CONSULT A COMMERCIAL/INDUSTRIAL ELECTRICAL DESIGN ENGINEERING COMPANY. Only a Registered Professional Engineer specializing in large commercial or heavy industrial power distribution systems is legally qualified to make these design decisions. Above and beyond that the building permits you will need to get require design plans to be filed with the city/state/whoever. Those plans literally require a PE stamp of approval on each and every plan. Period. End of story.
That said and strictly as a casual observation of what is done in large factories where my companies multi-kw hungry equipment (industrial lasers) and ancillary equipment are installed, yes odds are the design firm will go with 480v as the building distribution voltage. If anything, because at 480v the main switchgear 'only' has to handle 6,250A to deliver 3MW vs needing to be rated for 12,500A at 240v.
Frankly it would not surprise me if they go as high as 1.2kv for distribution as 3MW total load is certainly in the range to at least consider moving up to a MV (Medium Voltage) distribution network. Mainly would depend on the physical size of the farm and how far between the main panel and final step down transformer load points.