Last September's historic Southland blackout, which left communities from northern Mexico to Orange County and Arizona without electricity for almost 12 hours, stemmed from inadequate preparedness and subpar coordination among the agencies that operate the region's power systems, according to a government-industry report released today.
The analysis by the Federal Energy Regulatory Commission and the nonprofit North American Electric Reliability Corporation concluded that more "effective review and use of information would have helped operators avoid the cascading blackout.''
The outage left 2.7 million utility customers across the Southwest without electricity, forcing the closure of schools, offices, government facilities and businesses -- including gas stations -- throughout the region.
Commuters jammed roadways and ran out of fuel in lengthy traffic jams, medically fragile people packed hospitals, and others wound up trapped in elevators and on trolley cars.
In San Diego, the massive blackout also knocked out two city sewer-pump stations, causing spills of about 1.9 million gallons of wastewater into Penasquitos Lagoon, and some 125,000 gallons into Sweetwater Channel.
The outage began about 3:40 p.m. Sept. 8, when Arizona Public Service's Hassayampa-North Gila 500-kilovolt transmission line went down, officials said.
The region's power providers and system overseers proved unable to "ensure reliable operation or prevent cascading outages'' following that "single contingency'' in the grid, according to the report.
"That line loss itself did not cause the (regional) blackout, but it did initiate a sequence of events that led to the blackout, exposing grid operators' lack of adequate real-time situational awareness of conditions throughout the Western interconnection,'' the document states.
According to the report, "more effective review and use of information would have helped operators avoid'' the large-scale crisis.
"For example, had operators reviewed and heeded their real-time contingency analysis results prior to the loss of the APS line, they could have taken corrective actions, such as dispatching additional generation or shedding load, to prevent a cascading outage,'' the report states.
The eight-month analysis "highlights the growing need for more coordination of grid operations in the West,'' according to FERC Chairman Jon Wellinghoff.
"Implementing the recommendations in this report will assist in enhancing the planning and system-awareness measures that are necessary to operate an efficiently integrated bulk-power system and reduce costs to consumers from these types of outages, (which) could continue if operational efficiencies are not improved,'' Wellinghoff said.
Along with recommending that bulk power system operators improve "situational awareness'' through better communication, data-sharing and the use of "real-time tools,'' the report advises that:
-- System planners and operators recognize, study and incorporate the effects of sub-100-kilovolt systems on bulk-power system reliability;
--Transmission owners and operators review overload-protection relay settings to give them more time to mitigate overloads;
-- Transmission operators and the Western Electricity Coordinating Council study the effects of special protection systems and "safety nets,'' such as one that disconnected San Diego from high-voltage lines south of San Onofre Nuclear Generating Station, to understand how they affect reliability and to ensure that they do not have unintended or undesirable effects; and
-- System operators improve their ability to re-energize transmission lines following outages.
The massive blackout demonstrated "how complex and interdependent our North American electric systems are and the critical importance of information sharing, communications, system studies and coordinated operations among all interconnected systems,'' according to Gerry Cauley, president of the North American Electric Reliability Corporation.
"Transmission operators, balancing authorities and reliability coordinators must work together to effectively manage this complex system,'' he said.
