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Western Power Grid Changed Policies After '96 Blackout

by Times-News & Associated Press
Times-News, August 16, 2003

TWIN FALLS -- Westerners watching the Northeast cope without electricity from a distance know all too well what happens when the power grid fails.

The West lost power twice in the heat of the summer of 1996.

On July 2 that year, the Western power grid became overloaded, said Russ Jones, an Idaho Power spokesman. The heat was extreme and the electrical demand was high.

"Those lines have a tendency to sag," he said.

An overladen transmission line running from Idaho to Wyoming sagged enough to connect with a tree, he said.

The line short-circuited and the interconnected Western grid -- designed to allow utilities to trade around the region -- shut itself down.

Power was cut to 2 million customers in 14 Western states. The outage affected all of Idaho Power's customers from Pocatello to eastern Oregon and into Nevada.

Just a month later on Aug. 10, 1996, a second outage swept down the West Coast from Oregon into parts of Mexico and reached as far as Texas, affecting 4 million homes and businesses. A series of unrelated but coincidental events had stressed out the system: Two major high-voltage lines were out for maintenance and a third shut down when, once again, a transmission line "sagged into a tree," said Terry Winter, chief executive of the California Independent System Operator, a nonprofit power pool that oversees much of California's electricity grid.

The ISO was one of three regional security coordinating centers created by Western utilities after the 1996 blackouts.

The coordinators monitor the grid's power load, Jones said.

Since the 1996 blackout, Idaho Power has built more transmission lines from its main Hells Canyon hydropower complex to the Treasure Valley, he said.

"What the 1996 blackouts demonstrated was these things can rapidly roll out of control and it's very important to give early warning to everyone you're interconnected with," said Jan Smutny-Jones, executive director of Independent Energy Producers, a Sacramento-based trade association representing power plants.

Because electricity is often transmitted over vast distances from generating plants -- the United States has almost a half-million miles of bulk transmission lines -- the national grid system depends on more than 100 control centers that serve as choke points.

The centers reroute electricity to areas of high demand, and often have automatic switches. When a grid's distribution becomes unbalanced or overloaded, a blackout occurs. When severe, it can ripple across grids, sequentially shutting them down as circuit-breakers trip so equipment isn't damaged.

Post-mortems of the 1996 blackouts determined that the cascade of events might have been lessened had regional electrical utilities communicated better, providing early notice of potential problems.

A study by federal and state power regulators also recommended improved communications among grid managers. The utilities, power plants and grid operators set up plans to deal with potential blackouts that would give all parties early warning.

While too early to say whether Thursday's blackout in the Northeast might have been forestalled by improved communications, the interlocking grids back East have other problems. The U.S. Department of Energy says the main regional power pools involved -- chiefly New York and New England -- have weak transmission links that make it a challenge to move power to urban areas during peak periods.

Times-News & Associated Press
Western Power Grid Changed Policies After '96 Blackout
Times-News, August 16, 2003

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