Utilities watch Western grid

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Utilities watch Western grid Companies work to avoid blackouts like those in 1996

01/18/01 By Sean Deter and The Associated Press

In the vast interconnections of the Western power grid, which links Idaho to the western United States and parts of Canada, a seemingly innocuous event can have staggering consequences. At no time was that more apparent than in the summer of 1996, when a series of power failures left millions — many of them in the Treasure Valley — scrambling for their flashlights and wishing they had invested in gas-powered generators.

The first occurred July 2 and caught 1.5 million residents in eight western states off-guard. Among them were 700,000 southern Idaho, northern Nevada and Eastern Oregon Idaho Power customers who were caught in the grip of a blackout for several hours. At the time, no one could say what caused three major power lines near the California-Oregon border to fail. But after a smaller-scale version of the July 2 event hit the valley the next day, the source was discovered. & nbsp; Idaho Power’s Dennis Lopez said the culprit was a transmission line to the Jim Bridger Power Plant, near the Idaho-Wyoming border. Lopez said the line, after sagging from heat, became entangled in some poplar trees and “knocked the whole system down.” The events of Aug. 10 overshadowed the blackout a month earlier. A transmission line failed near Portland, Ore., leading to a cascading outage and blackouts that left 7 million people in the dark in 14 states.

Five years later, the infrastructure that delivers power to the West is under even more stress as demand increases without new sources of generation. And as power is being transferred in increasingly complex ways among 30 utilities on the grid, utilities are taking a variety of approaches to deal with the increased demand on resources. Lopez assured Idaho Power customers the trouble from 1996 is not likely to be repeated. The sagging line, he said, fell on the only stand of trees for miles in any direction. He called it a “freak accident.”

Since then, he said, the Western System Coordinating Council — a consortium of power companies that operate the grid — has stepped up security measures. Several security centers have been placed along the grid, which keep watch on the power loads running through the lines, Lopez said. Idaho won’t suffer the same problems as California. The two states’ electrical pictures are very different. Local power In 1999, Idaho Power Co. reported that nearly half of its electric power was generated by hydroelectric plants. A third came from thermal plants, such as those fueled by coal. The remaining 18 percent was purchased from other sources. “Their situation is a shortage,” Lopez said. “That’s what happened when they became deregulated. We don’t have a shortage.” The biggest problem Idaho Power faces is that the company probably won’t be able to generate enough of its own power during the coming year. The utility relies heavily — 60 percent — on hydroelectric power generated from 17 plants along the Snake River and a trio of dams near Hell’s Canyon. River flows are down considerably from last year. If conditions don’t improve, Idaho Power will have to purchase more power from outside providers. Although Lopez wouldn’t say how consumers would be affected, he did say those purchases would cost the utility a considerable amount of money.

Other parts of the West are turning to technological innovations for help. The interaction of generators and transmission requires intense monitoring to keep the lights on. ‘‘What this phenomenon does is limit the amount of power that can be safely transferred from one system to another before you put the system at risk of failure,’’ Jeff Dagle, a senior research engineer at the Pacific Northwest National Laboratory in Richland, Wash., said. ‘‘On Aug. 10, 1996, we found the edge was a little closer than we thought.’’ To minimize the chances of regionwide blackouts due to power failures or catastrophic events such as earthquakes, the Richland lab and the Bonneville Power Administration are using a system that quickly gathers information about supply and demand on the grid. The Wide Area Measurement System is an electrical ‘‘black box’’ of sorts, not entirely different from the mission of those used in aviation, to make it easier to get data, analyze it and share it so as to detect potential grid emergencies and minimize the chance of limited failure spilling across the network.

WAMS gathers data fast — 20 to 30 samples every second, compared with conventional means at most utility control centers, where data comes in at a rate of one sample every two to four seconds.

‘‘It’s critical to know what those limitations are. If the edge of safe operating conditions is reached, the net result is a cascading outage that can lead to blackouts,’’ Dagle says.


-- Martin Thompson (mthom1927@aol.com), January 19, 2001


An analogy from the movie "FailSafe": Stage 1 = Defcon 4. Stage 2 = Defcon 3. Stage 3 = Defcon 2. Controlled rolling blackouts = Defcon 1. And, an uncontrolled cascading blackout = Defcon ZERO. The lower the electric grid reserve margin, the higher the probability that an uncontrolled cascading outage will occur. With grid margins "at the edge" continuously, it is likely only a question of when a major uncontrolled cascading outage will hit. This is especially true, since there is no short term relief in sight, from chronically low grid reserve margins. Come summer, the situation is likely to get worse, not better.

-- Robert Riggs (rxr.999@worldnet.att.net), January 19, 2001.

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