Medium Voltage Short Circuit Protection

I'm doing my first medium voltage project :dunce:, and I'm trying to find a reference for how to size wires and circuit breakers/fuses. The only medium voltage devices that I have are a 1685HP motor, with a MV VFD controlling it. I look at 430 Part XI in the NEC and the guidelines are vague. It has language such as, "a circuit breaker of suitable type and rating" or "Protective device settings for each motor circuit shall be determined under engineering supervision". :? Can somebody point me in the direction of a good reference?
 
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