Final Report on the August 14, 2003 Blackout in the United States and Canada : Causes and Recommendations

This final report by the U.S.-Canada Power System Outage Task Force examines the electricity system before and during the massive power outage on August 14, 2003 which affected approximately 50 million people in the Midwest and Northeast United States and Ontario, Canada. The report identifies the causes of the outage and why they were not contained. It also gives recommendations to prevent or minimize future blackouts, some of which include implementing reliability standards and increasing the physical and cyber security of the network. The four group causes for the blackout have been identified as: (1) inadequate system understanding, (2) inadequate situational awareness, (3) inadequate tree trimming, and (4) inadequate reliability coordinator diagnostic support. This final report covers work done by 3 working groups which focused on the electric system, security and nuclear facilities. The chapters of this report dealt with the following issues: the North American electric power system and its reliability organizations; causes of the blackout and violations of North American Electric Reliability Council (NERC) standards; preconditions for the blackout with reference to the northeastern power grid before the blackout; how the blackout began in Ohio; the cascade stage of the blackout; the August 14 blackout compared with previous major North American outages; performance of nuclear power plants affected by the blackout; and, physical and cyber security aspects of the blackout. The report indicates that the loss of FirstEnergy's overloaded Sammis-Star line triggered the cascade. Its 345-kV line into northern Ohio from eastern Ohio began tripping out because the lines were in contact with overgrown trees. The loss of the line created major and unsustainable burdens on lines in adjacent areas. The cascade spread rapidly as lines and generating units automatically took themselves out of service to avoid physical damage. The blackout had many contributing factors in common with earlier outages including: inadequate tree trimming, failure to identify emergency conditions, inadequate operator training, and inadequate regional-scale visibility over the power system. refs., tabs., figs.