Looking for resources for determining cable requirements for high wattage (MW) applications
There are numerous current capacity or ampacity tables and voltage drop calculators online. Both metric and American Wire Gauge (AWG) are covered as well as wire temperature and voltage ratings. You may need to consider parallel conductors or bus bar at 2000 amps. In the USA, the tables provided in the National Electrical Code (NEC) must be used for ampacity. Tables are valid for a specific maximum ambient temperature look for derating factors in footnotes for higher temperature. Note also that the number of conductors in a conduit or raceway must also be considered. That is covered in NEC. Electrical codes in other parts of the world likely have similar tables and requirements.