The above example is an important one from the practical viewpoint since it indicates the order of magnitude of the frequencies which can be superimposed upon the nominal 60-Hz frequency in a large system having many interconnected
machines. As load on the system changes randomly throughout the day,intermachine oscillations involving frequencies of the order of 1 Hz tend to arise, but these are quickly damped out by the various damping influences caused by the prime mover,
the system loads, and the machine itself.