Hey, guys. We all know power of AC currents is transferred via EM waves, but we seldom use that to calculate power in AC system. The reason for this is wavelength is very long. I want to know if there is really existed a transmission line which is 500km, just the length of EM wavelength, then could we still use the traditional method to calculate AC system? For example, could we still regard the current in the line to be same in every spot?