Trees Touched Off August Blackout

WASHINGTON, DC, November 19, 2003 (ENS) - Causes of the August 14th blackout that left more than 50 million people across the northeastern United States and Ontario without power were spelled out today in an interim report by the Joint U.S.-Canada Power Outage Task Force.

The blackout began when three high-voltage transmission lines operated by FirstEnergy Corporation short-circuited and went out of service when they came into contact with trees that were too close to the lines, the task force found. FirstEnergy (FE) consists of seven electric utility operating companies in northeastern Ohio.

Power lines across the northeast United States and Ontario failed on August 14, 2003. (Photo courtesy NREL)

In addition, the task force said, the Midwest Independent System Operator (MISO) failed to provide effective diagnostic support to FirstEnergy once the power outages began to cascade.

Herb Dhaliwal, Minister of Natural Resources Canada, and U.S. Energy Secretary Spencer Abraham released the interim report today. It sets the stage for the next phase of the process - the development of recommendations aimed at reducing the possibility of future outages.

"Millions of people were inconvenienced, some were even endangered, and everybody wanted answers about what caused such a widespread power blackout. For the past three months, hundreds of technical experts and energy specialists from both the United States and Canada have been working to find those answers," said Abraham today.

"One major conclusion of the Interim Report is that this blackout was largely preventable," Abraham said. "However, the report also tells us that once the problem grew to a certain magnitude, nothing could have been done to prevent it from cascading out of control."

The task force blamed FirstEnergy, saying, the company "did not use an effective contingency analysis capability on a routine basis."

In addition, FE lacked procedures to ensure that their operators were continually aware of the functional state of their critical monitoring tools, lacked procedures to test these tools after repairs were made, and FE did not have additional monitoring tools for high level visualization of the status of their transmission system after the failure of their primary monitoring/alarming systems.

FirstEnergy President and Chief Operating Officer Anthony Alexander took issue with the task force's findings. He acknowledged that "a previously undetected flaw in vendor software that resulted in the loss of an alarm function," affected operators' "understanding of events on our system" that day.

But, Alexander said, "most experts agree that the network was stressed and being asked to perform in ways for which it was not designed."

The task force, made up of working groups co-chaired by both countries, said "the August 14, 2003, blackout was caused by deficiencies in specific practices, equipment, and human decisions that coincided that afternoon."

The task force’s investigators found that at on August 14 at 15:05 EDT, immediately before the first event in the blackout, the automatic shutdown of FirstEnergy’s Harding-Chamberlin 345-kV transmission line, the system was in a "reliable operational state." This "extremely significant" finding means, the task force said, that none of the electrical conditions on the system before that time was a direct cause of the blackout.

The blackout was not caused by: high power flows to Canada, system frequency variations, low voltages earlier in the day or on prior days, low reactive power output from Independent Power Producers, or the unavailability of individual generators or transmission lines, the task force said.

FirstEnergy President and Chief Operating Officer Anthony Alexander (Photo courtesy Ohio Electric Utility Institute)

"Our transmission system was designed and built to provide reliable service to our customers, not to be a superhighway for long distance transactions to Canada and elsewhere," said Alexander. "Yet, on August 14, the margins built into our system for serving our customers were being drained by those transactions, with little or no reactive power support to the grid for those sales."

If the final task force report fails to consider these regional, underlying and contributory causes of the outage, said Alexander, "we believe that the task force will not achieve its goal of ensuring that widespread outages are not repeated."

But the task force focused instead on trees. FE’s 345-kV transmission lines began "tripping out" because the lines were contacting overgrown trees within the lines’ right-of-way areas. "This failure was the common cause of the outage of three FE 345-kV transmission lines," the report says.

MISO, the reliability coordinator for FirstEnergy, was responsible for the blackout too, the task force said. MISO handles a region of more than one million square miles, stretching from Manitoba to Kentucky, from Montana to western Pennsylvania.

In the three hours before the blackout officially began at 15:05, three power lines shut down, or tripped. One of them, the Dayton Power and Light (DPL) line, known as the Stuart- Atlanta 345-kV line in southern Ohio, tripped at 14:02.

But MISO did not have real-time data from the Stuart-Atlanta 345-kV line incorporated into its system monitoring tool, the task force said, and, "This precluded MISO from becoming aware of FE’s system problems earlier and providing diagnostic assistance to FE."

In addition, MISO’s reliability coordinators were using non-real-time data to support real-time monitoring functions, said the task force. This prevented MISO from detecting a security violation in FirstEnergy's system and offering assistance.

MISO lacked an effective means of identifying the location and significance of transmission line breaker operations, and so were not aware of important line outages in time to prevent the blackout, the task force said.

The North American Electric Reliability Council (NERC), made up of utility operators across the United States and Canada, affirmed its "full support" for the findings of the task force that was released today. NERC, along with some of North America’s leading power system experts, helped the task force with its investigation.

“The interim task force report completely and accurately describes the major events - electrical, computer, and human - leading up to the August 14 blackout, and identifies the causes of the blackout,” said Michehl Gent, NERC president and CEO.

"The Electric System Working Group has concluded that at least four reliability standards established by NERC were not observed by FirstEnergy on August 14th, and two were not followed by MISO," Secretary Abraham said today. "These failures helped create a problem of such magnitude as to be insurmountable."

Gent says the report underscores the need for legislation that would make electric reliability standards mandatory and enforceable. “As unfortunate as the blackout was, our analysis indicates that it was also preventable and clearly demonstrates the immediate need for mandatory standards.”

The next phase will be the development of recommendations aimed at reducing the possibility of future outages. As one part of this process, in early December, the public and stakeholders in both countries will be asked to give their comments on the report and their views on enhancing the reliability of the electricity system.

The Final Report of the Task Force will focus on identifying specific recommendations to reduce the likelihood of future blackouts and bolster the reliability of the electricity infrastructure.

The Interim Report: Causes of the August 14th Blackout in the United States and Canada is online at: https://reports.energy.gov/814BlackoutReport.pdf