Well, isn't that a lovely question! To power a 20kVA load over 320 meters, you'll want to use a cable size that can handle the electrical current without losing too much energy along the way. I recommend consulting with a local electrician or engineer to determine the specific cable size needed based on factors like voltage drop, cable type, and installation conditions. Just remember, with the right guidance, you'll create a beautiful and safe electrical connection for your needs.
A rough guide is to divide kVA by the supply voltage then multiply by 1000 to get current in Amps. E.g. 20kVA divided by 120V is 0.167; times 1000 is 167 Amps. But kVA is not the same as kW, so more information is needed before equipment is used.