How Can excitation wave move from node of Ranvier to another in myelinated nerve fibers?

They don't really move as a "wave" in the case of myelinated fibers - they sort of hop between nodes in a process called saltatory conduction. The electrical impulse is conducted through the cytoplasm of an axon - the problem is, the membrane of an axon is also conductive, so if you apply a charge to one segment of an axon, the charge dissipates out of the cell after a short distance. In an unmyelinated axon, a charge can only depolarize the segment of membrane right next to it, which depolarizes and opens the ion channels in  the next segment, replenishing the charge, and so on, and therefore sort of inches along as a relatively slow wave of depolarization. In contrast, the myelin in an myelinated cell works as an insulator, reducing charge loss through the membrane. Therefore, since less charge is lost out of the cell for a given distance, the change in voltage can be maintained across a greater distance (i.e. to the next node of Ranvier), where it is still enough to depolarize and open the ion channels to regenerate the charge, thus "hopping" between nodes. I guess another way to look at it would be to think of an unmyelinated fiber as a bunch of nodes of Ranvier stuck together - since ion channels are physical structures which take a finite amount of time to open and close, it then becomes easy to see how conduction is much faster in myelinated axons where you have to open far fewer channels per given unit of distance.