North American Electric Reliability Corp. CEO Rick Sergel on February 27 applauded the efforts on February 26 by Florida utilities to restore power after a system disturbance in south Florida led to the loss of about 12 power plants, 26 transmission lines and cut power to millions of customers.

NERC, which is responsible for establishing and enforcing mandatory reliability rules for the electric power industry, categorized the event on February 26 as a "Category 4" system disturbance.

NERC said its event classification system designed to designate the severity of bulk power system disturbances has five levels, with Category 5 the most severe.
NERC's analysis will attempt to find and recommend specific preventative measures that could be adopted to ensure that similar disruptions are avoided at other locations in the future.

"We commend the restoration efforts conducted by the affected utilities yesterday," Sergel said in a statement.

"Their ability to restore power quickly and effectively to the hundreds of thousands of consumers affected by the outage clearly exemplifies excellence in planning and the execution of those plans."

Sergel said reports have indicated that nearly all affected consumers had power restored by 4:15 pm EST on February 26.

Sergel, who said NERC is investigating the disturbance, added that "[w]hile we can't predict the timetable of analysis, information collected by new monitoring technologies, called 'synchro-phasors,' will enable our teams to analyze yesterday's outages more quickly than in the past. This new technology is like the MRI of bulk power systems, giving operators and analysts more granulated data and helping them to dissect and piece together the events that occurred step by step, microsecond by microsecond."

Late on February 26, NERC said it would try to identify "preventative measures" transmission grid operators could adopt to avoid disruptions like the one on February 26.

NERC said customers of at least four utilities in Florida lost power when some 2,700 MW of generation and 15 transmission lines were affected by an incident that started at 1:09 pm EST on February 26.

The loss of generation activated automatic under-frequency load shedding equipment and more than 4,000 MW of load was shed in many parts of the state, NERC said.

NERC said it, the Florida Reliability Coordinating Council and other involved parties will examine the event. NERC and FRCC also will examine compliance with NERC's reliability standards, which now are mandatory and regulated by the Federal Energy Regulatory Commission.

Violations of the standards can trigger a range of enforcement actions, including fines of up to $1 million per day.

"NERC's analysis will attempt to find and recommend specific preventative measures that could be adopted to ensure that similar disruptions are avoided at other locations in the future," the reliability organization said.

NERC officials said the initial inquiry will focus on an equipment failure at a Florida Power & Light substation. While a fault at the substation appeared to be the starting point for the outage, it also appeared that relays on transmission lines did not isolate the fault as they are designed to do, Stan Johnson, director of situation awareness at NERC, said.

"What we don't know is why the initial fault wasn't cleared quickly, which led to the undervoltage impact" that caused power plants to be shut down, he said.

Created: February 27, 2008