Posted on 08/15/2003 4:24:37 AM PDT by Squawk 8888
TORONTO (CP) - A massive power outage that blacked out most of Ontario and several states in the northeastern United States on Thursday afternoon showed the deep interdependence of the North American power system.
Canada trades significant quantities of electricity with the United States. Quebec is a major exporter to the northeast United States and together with Newfoundland and Labrador plans to make important expansions in electricity generating capacity.
And the electricity grids in Canada and the U.S. link at 37 major points.
Exports represent approximately seven per cent to 10 per cent of total Canadian generation and 1.2 per cent of total U.S. consumption, with export volumes growing steadily from 1990 to 1994. They have been stable since.
U.S. imports into Canada have increased significantly over the last few years, peak demands in different time zones accounting for much of the growth.
Ellen Vancko, spokeswoman for the North American Electric Reliability Council, said the grid affected extends from the Rocky Mountains to the Atlantic and from the Gulf of Mexico to Hudson's Bay.
"The northeast part of that grid is where all the problems are occurring. We've managed to keep it from spreading to the rest of that interconnection," Vancko said.
"We're still trying to put it back together, we'll worry about why it happened later."
Power transmission in North America is directed by control centres where experts monitor the distribution of power and reroute electricity from areas of low demand to areas of high demand. Often there are automatic switches that direct the routing of power to where it is needed.
From the high voltage transmission lines, power goes to regional and neighbourhood substations. There, the electricity is stepped down from high voltage to a current that be used in homes and offices.
High or unbalanced demands for power that develop suddenly can upset the smooth distribution of electricity in a grid. In some cases, this can cause a blackout in one section of a grid, or even ripple throughout the whole grid, sequentially shutting down one section after another.
Once large sections of a grid are shut down, it may be difficult or impossible to restore power from neighbouring grids. In periods of high demand, such as summer, often those nearby grids also are under stress and may not have spare power.
When power is restored, it can cause a sudden surge in demand that the system may not be able to accommodate. When electric motors, transformers and other electrical devices are all energized at once, it can draw many times the normal load and can trip a secondary shutdown.
North America has major electric power grids but does not have an overall, comprehensive grid. Within the area of the NERC councils there are three major systems - the Eastern Power Grid, the Western Power Grid, and the grid within the Electric Reliability Council of Texas - that have limited cross-grid interconnection capability.
In addition, there are interconnection compatability issues outside the NERC councils, particularly between Mexico and the United States.
In 1965, a power outage blacked out the entire eastern seaboard after a burst of 1,100 megawatts of electricity from the Sir Adam Beck No. 2 station at Queenston, Ont.
Power was moving into Ontario through Niagara from upstate New York when there was a failure in a 345,000-volt line south of Niagara Falls, N.Y. A subsequent surge of electricity sent power flowing into the system at Cornwall, Ont., in the opposite direction of the flow at that hour.
The power shortage sped through the grid, hitting upstate New York, Massachusetts, parts of Vermont, New Hampshire, Connecticut and New Jersey as their generators shut down.
"The reason NERC was created was to prevent that sort of thing from happening or at least minimize the chances, but of course in an interconnected system such as complex as ours it can happen and obviously it has. We just don't know why yet," Vancko said.
Who is National Grid USA? Who is National Grid Transco? [[Outage] vanity]
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