just a minor note ont he initial cause. They grounded the system just fine,
then just forgot to pull the safety grounds before they repowered the line.
As for "power grid outages shouldn't spread", there's a rule in that biz, it's
always easier/faster to reset 10 circuits that replace something. If you leave
a turbine generator up in a situation where output load is whacked, you could
be looking at a several week outage. The reason it took them so long to get
the plants back on line is they have to do a complete system inspection to
make sure the breakers tripped in time.
One other thing to remember, there isn't a whole lot of risk working on a
router outage. When you're restoring electric service, you have to go slower
so you keep the possibility of frying a lineman to a minimum. I spent a few
weeks installing power line electronic equipment in a 115kv substation and got
a whole new level of respect. You couldn't pay me enough to do that work (but
I like their trucks.)