LAX Airport is having widespread power outages, flights being rerouted...

A complex that large is most likely served by several independent substations with power coming from different directions, and each serving different buildings. Reasons are cost efficiencies, maintainence, and the electrical codes. Back-up for the whole place is cost-prohibitive. Only critical life safety needs are on generators or batteries.

"The outage struck about 6:30 p.m. Wednesday and was caused by a power 'bump' at an off-airport Los Angeles Department of Water and Power substation, which caused a power disruption throughout the airport, according to airport officials. It caused 21 flight cancellations and at least seven diversions of flights, according to an airport official.

Power was restored within an hour to terminals 2, 3, 4, 5 and 6 and the Tom Bradley International Terminal. Terminals 1, 7 and 8 remained with only emergency power."
http://www.foxla.com/web/kttv/news/local-news/terminal-1-evacuated-at-lax-to-be-re-screened-by-tsa-following-power-outage

One terminal has been evacuated.