[meyer]

The entire eastern portion of the US, from east of the Rockies on to the Atlantic is pretty tightly connected, with the exception of Texas which has a few ties to the eastern grid, but nothing too strong. The acronyms, ECAR, MAAC, and the like are arbitrary boundaries dividing the various regions that manage the grid - they aren't disconnected from each other. If one had a map showing the major transmission lines in the areas affected and those around them, one would probably see a pretty good pattern of how the events unfolded. I suspect that over the next few weeks, information taken from substation event recorders and control center computers will tell the tale quite thoroughly.

[Helix]

Thanks for the explanation. I was pretty young during the blackout in 1977, but I think there had been some debate about "insulating" sections of the grid from one another and building better backups into the system. If it's feasible, we might ought to consider having smaller, more independent, power grids.

[BohDaThone]

Here's my understanding:

There are contingency plans to keep a simple accident from taking down the whole system, and virutally all the time they work. Sometimes they don't. After the 1965 and 1977 massive East Coast blackouts, there were extensive investigations, just like after a plane crash, (And, yes, there are voice recordings of the various control rooms -- the tapes of the 1977 blackout, largely caused by an operator not following the plan, are hilarious, if not somewhat tragic). Electrical grids are very complex systems, and, in a sense, it is a "miracle" -- caused by human ingenuity every day, that it hangs together 99.99% of the time. We'll see what the after action investigation shows this time. SAMPLE CONVERSATION from 1977: Operator 1: (Not in NYC) -- Yep, he's down the dumper. Operator 2: I told him to shed load -- my needles are all flat (no power going in to NYC). Operator 3: I agree -- he's down the dumper. [The operators were people on the grid operating team, in Maryland, Canada, or whereever, who were trying to feed more power to make up for the loss when lighting took out a connection point north of NYC. The plan called for NYC to blackout some parts of the city, to help out -- However, the big boss was home in Queens, and the on the spot operator was too timid to either take action or call the boss at home -- result -- no load was cut, and NYC dragged the whole system down, as the lost power couldn't be replaced fast enough -- the other suppliers finally had to cut off NYC to keep their own systems from going down, too.] --------------------------------------------------------------------------------