Re: Why Standing Wave is discuss only in RF Transmission Lin
Yes, the wavelength of a 50Hz voltage travelling conductors is about 300000000/50 = 6000 km. It has the same properties as others signals (rf, digital,...).
I think that you're confused with two things.
On the first hand is the propagation of the electromagnetic wave associated with the 50Hz voltage (or any DC voltage), think about a switch that light a bulb (it's instantaneous since the velocity of the current wave is always in the range of the speed of light, it's a real wave along conductors between the switch and the bulb and is not related with the charge displacement).
On the second hand, the displacement of the charges (electrons), these ones have very low speed (depending also strongly of the medium) and, of course, in AC current their mean velocity = 0 (since they always go-back).