5.3 Million People Lose Power Due to Routine Maintenance
Shut down of the San Diego Airport.
Huge traffic snarls (this occurred at around 4:00pm local time).
Shut down of 2 nuclear reactors (the shutdown was per procedure for a loss of load).
Over 1 million gallons of sewage spilled into the ocean due to loss of sewage treatment capability, closing San Diego beaches.
Was this caused by a huge lightning strike? An enormous traffic accident? A transformer explosion at a substation? Nope. In this case, it was a maintenance error. A maintenance worker was changing out a piece of monitoring equipment, and for some reason (not yet determined) the power tripped. Of course, there are safeguards that should localize this trip to a small area. However in this case those safeguards did not work (not sure why), and a 500,000 volt power transmission line also tripped off-line. This main feeder dropped power to a significant portion of the southwest U.S.
The company is initiating a root cause analysis to understand the reasons for the outage.