or several years, as growing summertime surges
of power criss-crossed the web of transmission lines in Ohio and the
rest of the Midwest on their way to Manhattan or Toronto or Detroit,
utility and government monitors grew increasingly concerned about
the risks of straining the system.
Problems on the lines were becoming more frequent, and a series
of reports, by the industry's own quality-control offices and
government agencies, described the risks and urged utilities to be
more aware of the physical limits of the Midwest system.
The complexity and magnitude of the power flows, one report by
the Federal Energy Regulatory Commission said, could "overwhelm the
electronic and software tools used to model and manage power flows
on the grid."
So when an hourlong series of line failures and plant shutdowns
suddenly exploded on Thursday into North America's biggest blackout,
few experts were surprised at where it had begun.
"Reliability here," said Dr. Stephen A. Sebo, an electrical
engineering professor at Ohio State University and a member of the
Ohio Power Siting Board, "is unquestionably a
Now it is the focus of an international inquiry. And Midwestern
and Ohio power managers and the FirstEnergy Corporation, an Akron utility that struggled for
an hour before the full catastrophe to deal with the failure of
several of its lines, find themselves enduring intensifying scrutiny
Among the questions officials want to answer is whether anything
was done by Midwestern or FirstEnergy officials to alert neighboring
regions to the growing crisis. They may also want to determine
whether enough was done over the years to manage the Midwestern
system responsibly. Finally, the fact that the blackout occurred on
a day of only ordinary summer demand suggests the problem lay with
the way the system was managed and not with a lack of capacity, some
At FirstEnergy, Todd Schneider, a spokesman, said yesterday that
the company was far from ready to say that the precipitating event
was the failure of four of its lines and one co-owned by American
Electric Power. Three hours earlier, he said, there were signs of
instability on the grid outside FirstEnergy's service territory. He
would not say where they occurred, but said they could have played a
"There were situations throughout the region that may have
contributed to the event, not just these power lines in our system,"
FirstEnergy distributed a statement on Saturday saying that it
had failed to notice the line failures because an alarm system
designed to alert its operators was not working.
Yesterday, Mary Lynn Webster, a spokeswoman for the Midwest
Independent Transmission System Operator, the industry group that
monitors the flow of power throughout the region, said that during
the escalating problems in Ohio, at least three conversations took
place between coordinators from that group and FirstEnergy to
discuss the line failures. She said tapes of the conversations would
Power managers in adjacent parts of the grid, including the
Northeast, said they were concerned that there was no early warning,
adding that such an alert might have helped them gird for what one
official called the eastward-pulsing "shock wave" that triggered the
Last night, leaders of an industry investigation of the blackout
said it was too soon to assign blame.
"What we really need to focus on now is why protective schemes
that should have localized the impact of various events did not
work," said Michehl R. Gent, the president of the North American
Electric Reliability Council, a nonprofit industry group set up
after the blackout of 1965 to cut the risks of such failures.
Its inquiry is just one of a host of investigations trying to
unravel how a building parade of problems around Ohio was not
isolated before the problem crossed the maze of lines linking the
Midwest and the East, which collectively are called the Eastern
There, within nine determinative seconds, the problem exploded
into a power failure affecting 9,300 square miles and millions of
The investigators range from teams dispatched by dozens of
individual companies inspecting gear and records for strained or
failed equipment to an international task force created by the top
energy officials in the United States and Canada. They will need to
disentangle what Mr. Gent described as more than 10,000 "discrete
system events," scattered over thousands of miles of interconnected
systems as big as a billion-watt power plant and as small as the
diameter of a high-tension power line.