Sharon Bernstein, Patrick McGreevy and Mitchell Landsberg
Los Angeles Times
Los Angeles -- A mistake on a single power line Monday cascaded into a major blackout in and around Los Angeles, inconveniencing millions of people and renewing questions about the vulnerability of the region's power system.
Coming one day after a purported al Qaeda threat of attack on the city, the mid-day outage pricked nerves and caused isolated incidents of panic. Plumes of flame and smoke heightened the drama as refineries, temporarily shut by the power failure, flared off excess gases.
But backup generators, many newly installed since California's 2001 energy crisis, kept many companies and most emergency services operating without major disruption, and there were no reports of deaths or serious injuries caused by the blackout.
The Los Angeles Department of Water and Power, the city-owned utility, said the outage had occurred while its employees were cutting wires at an electrical transmitting station in Toluca Lake while installing a new electrical monitoring system.
The mistake rippled through the electrical grid, threatening to overload another transmission station and two electrical generating plants.
DWP shut down the generating facilities to avoid damage, sharply reducing the amount of power available for the city. That caused blackouts in neighborhoods scattered across the city, with heavy concentrations in parts of the San Fernando Valley, south Los Angeles and the downtown area.
"This strikes me as something under the category of unbelievably bad luck, where you cut one line and have that kind of cascading effect," said Bob Finkelstein, executive director of The Utility Reform Network in San Francisco, a consumer advocacy group.
The new, automated system workers were installing was meant to detect surges or drops in voltage, said Ed Miller, the DWP's director of power systems, operations and maintenance.
"They cut a bundle of wires," Miller said. "The supposition is that by cutting them together they created a short that triggered the circuit breakers." Miller said cutting wires one by one might have avoided an electrical short.
The outage occurred at 12:37 p.m., cutting power to 750,000 homes and businesses, or about 2 million people, DWP officials said. It struck slightly more than half of DWP's service area. Other parts of the region, most of which is served by Southern California Edison, were not affected.
Power was restored to 90 percent of the downed customers within 90 minutes, DWP officials said.
Though some power experts said the system had performed correctly given the surge, it was the latest indication of the electrical grid's vulnerability.
Two weeks ago, half a million Southern California Edison and DWP customers lost power for 30 minutes when a transformer shut down automatically because an alarm mistakenly went off.
The Associated Press contributed to this report.
