Yep, as others have pointed out, grid operators can see waves of frequency change propogate through the system. Here’s some visualizations of that (see the lin

Yep, as others have pointed out, grid operators can see waves of frequency change propogate through the system. Here’s some visualizations of that (see the linked movies) from a cool project called FNET/GridEye: http://fnetpublic.utk.edu/sample_events.html http://fnetpublic.utk.edu/sample_events.html