to give you some guidance - the cable has to be rated for the intended voltage. So if you intended to use 480V - you're cable needs to be rated for 480V.
Cables are also rated for a particular load - add an appropriate margin above 35KVA and ensure the cable is rated for that particular load.
If there are thermal limits involved - look at the temperature rating of the cable.
You'll also need to determine the cable impedance (real and reactive) for line loss and protective relaying.
check out IEEE Red Book™— IEEE STD 141™-1993 (R1999), Recommended Practice for the Electric Power Distribution for Industrial Plants
Also checkout
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http://gpac.link/1usweRtSymmetrical Components:
http://gpac.link/175IP7B
