I have a frayed psu to cpu cables. I am wondering if EVGA sells these cables individually as I would hate to have to buy an entire new set.

This is why I recommend a fully modular PSU. If you don't have fully modular a frayed cable can not be a easy fixed. It's not just about being able to replace the cables for cosmetic reasons. 

Vlada011
How you frayed PSU cable?
 

I think I saw this person's earlier post here or on reddit, but if it's the same person they ran their cpu power cable by a top-mounted clc and the cable ended up hitting the fan blades.  I had the same thing happen to me when I first installed my clc at the top of my case and wasn't paying attention to the fan's outer casing being tapered/not as protective.  Fortunately, I noticed the sound and caught it within a few minutes so no damage done.
 
I'd also like to add that EVGA RMA replacements sometimes leave customers with modular cables they're not using anymore (my GS was replaced with a G3, for example) so with a bit more info about where a person is and what psu cable they're trying to replace might even enable the community to help provide single-cable support, but EVGA's official crew isn't slouching either.