Station A goes off line, due to an over current trip, the rest of the Grid has to make up for the loss in Generation capacity, meaning that Stations B,C,D and E have to carry the load of Station A, too.
This is just not possible, meaning that Stations B,C,D and E, will eventually trip out through over-current, hence the Black-out effect.
Maybe tomorrow's grid will have to be designed to be a little smarter than just dumping station A's load onto other stations.
It would have to be something like this:
Station A trips out due to overload, so a computer looks at the demand and the capacity of stations B, C, and D and determines what demand can reasonably be met.
It would then have to:
(a) disconnect low-priority loads further downstream by sending various commands to lower-voltage stations, then
(b) transfer the HV lines previously on station A to B, C, and D.
