I finally found an artcle about what Philly News was talking about
http://www.philly.com/mld/philly/6535637.htm Posted on Thu, Aug. 14, 2003
Safety steps stopped spread of outage.
By Akweli Parker and Tom Avril
Inquirer Staff Writers
Technicians in Valley Forge saw the sudden power surge. Circuit breakers tripped. And within four minutes, the electricity grid that serves Pennsylvania and New Jersey had clamped off the spike that blacked out much of the Northeast today, shielding Philadelphia and points south from the disruption.
As a result, the Mid-Atlantic grid, operated by Valley Forge-based PJM Interconnection L.L.C., experienced only a few spillover blackouts in sections of northern Pennsylvania and northern New Jersey.
It was the kind of moment PJM's technicians practice for, company president Phillip G. Harris said: "Coordination is rehearsed and drilled several times a year."
Details on exactly what triggered the blackout were still sketchy today. Canadian officials blamed the blackout on a lightning strike at the Niagara power plant, and U.S. officials said they were looking at a power transmission problem from Canada as the most likely cause.
The outage affected a huge swath of the Northeast, stretching from New York to New England to Ohio.
PJM's quick action, coupled with ample power-generating capacity throughout the region, kept the incident from crippling Philadelphia, Harrisburg and Washington, Harris said.
Technicians fed reserve power into the grid to smooth out irregularities caused by the surge - keeping the region's lights on.
The Nuclear Regulatory Commission reported that nine nuclear reactors at seven sites, including the Oyster Creek plant in Lacey Township, Ocean County, N.J., shut down automatically, as they are designed to, when they lost their off-site power supplies. It could take 24 hours or more to restart them.
PJM runs what it says is the largest wholesale electricity market in the world. It projects electricity demand for an area that is home to more than 25 million people, then accepts bids from electricity generators and wholesalers to supply the needed energy.
It also is responsible for making sure electricity is available reliably throughout its Mid-Atlantic grid, a system that supplies power to all or parts of Pennsylvania, New Jersey, Maryland, Delaware, Virginia, Ohio, West Virginia and Washington, D.C. Among the companies that participate in the grid are Peco Energy Co. and Public Service Electric & Gas Co.
David Sanko, director of the Pennsylvania Emergency Management Agency, said at least parts of seven counties in the northwestern section of the state lost power: Erie, Crawford, Warren, Venango, Clarion, Forest and Bradford. A power outage reported in Adams County, west of Harrisburg, was unrelated.
Sanko said power was beginning to be restored by 6 p.m.
Hospitals and other emergency facilities in the affected counties continued to operate using backup generators, he said.
"The benefits of the system is the immediate isolation of [the problem] so the rest of the state was not affected," Sanko said.
PJM technicians saw electricity usage in the area under their control drop suddenly by about 5,200 megawatts shortly at 4 p.m. One megawatt is enough electricity to power 750 to 1,000 homes.
"The protective equipment did work . . . it operated exactly like it's supposed to," Harris said.
That said, no electric grid is bulletproof, said Chika Nwankpa, professor of electrical and computer engineering at Drexel University.
"During high-temperature conditions, all [regional power operators] are vulnerable," said Nwankpa, who has worked with PJM and several of the region's electric utilities on assorted projects.
Often, blackouts occur when the demand of electricity customers is greater than the amount of electricity being cranked out by power plants.
Likely a number of giant circuit breakers, typically located in a free-standing building at least 40 feet tall, automatically tripped so that dangerously high current did not flow into the Pennsylvania-New Jersey-Maryland region. Otherwise, according to Vijay Vittal, professor of electrical engineering at Iowa State University, there would have been problems over an even wider area.
"If such a large area was affected, it must be a very severe disturbance," said Vittal, member of a national industry-university research group that studies the reliability of the power system. "It could have spread to your area. . . . If nothing had been done, it could have probably extended out to Iowa and Nebraska."
Protective circuit breakers apparently did not activate quickly enough to protect the region containing Cleveland and Detroit, Vittal said.
"All this happens in fractions of seconds," Vittal said. "This is a very classical cascading outage."
Once the power comes back on, engineers will conduct a postmortem of the accident, relying on a real-time computer record of the current flows throughout the system, he said. Using the data, the engineers will run a computer simulation and try to re-create what happened, Vittal said.
Interesting article. So if they could prevent the spread, why couldn't other cities?
I also found this interesting -- what was the disturbance?
"If such a large area was affected, it must be a very severe disturbance," said Vittal, member of a national industry-university research group that studies the reliability of the power system.