POWER LINES
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In Brief
On August 14, 2003, shortly after 2 P.M. Eastern Daylight Time, a high-voltage power line in northern Ohio brushed against some overgrown trees and shut down—a fault, as it's known in the power industry. The line had softened under the heat of the high current coursing through it. Normally, the problem would have tripped an alarm in the control room of FirstEnergy Corporation, an Ohio-based utility company, but the alarm system failed.
Over the next hour and a half, as system operators tried to understand what was happening, three other lines sagged into trees and switched off, forcing other power lines to shoulder an extra burden. Overtaxed, they cut out by 4:05 P.M., tripping a cascade of failures throughout southeastern Canada and eight northeastern states.
All told, 50 million people lost power for up to two days in the biggest blackout in North American history. The event contributed to at least 11 deaths and cost an estimated $6 billion.
So, five years later, are we still at risk for a massive blackout?
In February 2004, after a three-month investigation, the U.S.–Canada Power System Outage Task Force concluded that a combination of human error and equipment failures had caused the blackout. The group's final report made a sweeping set of 46 recommendations to reduce the risk of future widespread blackouts. First on the list was making industry reliability standards mandatory and legally enforceable.
Prior to the blackout, the North American Electricity Reliability Council (NERC) set voluntary standards. In the wake of the blackout report, Congress passed the Energy Policy Act of 2005, which expanded the role of the Federal Energy Regulatory Commission (FERC) by requiring it to solicit, approve and enforce new reliability standards from NERC, now the North American Electricity Reliability Corporation.
FERC has so far approved 96 new reliability standards.* These cover the three Ts—"trees, training and tools"—identified by the blackout task force but are not limited to them, says Joseph McClelland, director of FERC's Office of Electric Reliability, which was established last September. Standard PER-003, for example, requires that operating personnel have at least the minimum training needed to recognize and deal with critical events in the grid; standard FAC-003 makes it mandatory to keep trees clear of transmission lines; standard TOP-002-1 requires that that grid operating systems be able to survive a power line fault or any other single failure, no matter how severe. FERC can impose fines of up to a million dollars a day for an infraction, depending on its flagrancy and the risk incurred.
If the standards have reduced the number of blackouts, the evidence has yet to bear it out. A study of NERC blackout data by researchers at Carnegie Mellon University in Pittsburgh found that the frequency of blackouts affecting more than 50,000 people has held fairly constant at about 12 per year from 1984 to 2006. Co-author Paul Hines, now assistant professor of engineering at the University of Vermont in Burlington, says current statistics indicate that a 2003-level blackout will occur every 25 years.
He says many researchers believe that cascading blackouts may be inherent in the grid's complexity, but he still sees room for improvement. "I think we can definitely make it less frequent than once every 25 years."
The U.S. power grid consists of three loosely connected parts, referred to as interconnections: eastern, western and Texas. Within each, high-voltage power lines transmit electricity from generating sources such as coal or hydroelectric plants to local utilities that distribute power to homes and businesses, where lights, refrigerators, computers and myriad other "loads" tap that energy.
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11 Comments
Add CommentI feel quite astnished as 45 years ago, when I was a student in electrical engineering, here in Li�ge (Belgium) I spent my hollidys working in an electric power plant on the subject "Phase-energy control system in the national grid.
Reply | Report Abuse | Link to thisVery few electronic components and systems where available at that time but the old fashionned "relay logic" was able to do the job in Belgium. The current status was to expand the geographic aspect to the next countries, France, Germany and others. What was USA doing since that time? I apologise for my english writing (french would have been easier for me !)
I feel quite astnished as 45 years ago, when I was a student in electrical engineering, here in Liege (Belgium) I spent my hollidys working in an electric power plant on the subject "Phase-energy control system in the national grid". Very few electronic components and systems where available at that time but the old fashionned "relay logic" was able to do the job in Belgium. The current status was to expand the geographic aspect to the next countries, France, Germany and others. What was USA doing since that time? I apologise for my english writing (french would have been easier for me !)
Reply | Report Abuse | Link to thisAlright. As a person with no power experience, but with an extensive background in analog electronics I have to say that I am throughly confused by this article. A number of statements are made that simply fly in the face of long established knowledge.
Reply | Report Abuse | Link to this1) "One of the realizations since 2003 is that "you can't just look at your system. You've got to look at how your system affects your neighbors and vice versa," [...]
It has long been known that you have to have information about neighboring sections of a net if you expect to be able to do anything other than react blindly to changes. It's the nature of power flow in a net! If they're refering to comprehensive knowledge of every node by every other node I'd have to agree that it'd make for a more stable system, but this is prior art and not a discovery. And for it to be fully utilized layers of regional and global supervisory systems have to be created. Perhaps this is what is being refered to but not including these things is not based upon sound knowledge of how to run these systems. Perhaps they're trying to soften their admission on long standing bad practices.
2) "That level of resolution across a network of PMUs could reveal an important electrical property of power lines called phase, which tells whether power generators are rotating in sync with respect to one another, Hines says."
This is astonishing to me. Phase is an essential quantity that must be known at every node for even the simplest systems to be able to work without blowing themselves up. Once again, it's the nature of the beast. Phase has to not only be established before initiating connections but it must be maintained carefully on a moment by moment basis if the net is not to detroy itself. Allowing phase to drift will produce instabilities all by itself and these instabilities are typically underdamped and lead to self destructive oscillations. This has always been known since the earliest attempts (and failures!) to connect systems and I've been told that phase is and has always been carefully monitored. Once again I'm told of a "discovery" that would have made operation of the system impossible up to now had it not been known!
At least the trend towards DC transmission will eventually eliminate phasing problems and reduce the total required knowledge to just load sharing. (Although, extended DC networks still have AC behavior and damping in some form has to address instabilities potentially becoming oscillations.)
i think that this major power failure was caused by a bunch of idiots who dont know how to install a proper security system. seriously this is like million dollar equipment and the government trusts idiots to put up the system. why would they do this if you reach into your money grubing pockets to pay someone real money. This would have saved more money if you only payed a little bit more money. Silly government just doesnt know what their doing.
Reply | Report Abuse | Link to thisYou have no idea what you're talking about. Government doesn't run control centers. Power companies do. Security had nothing to do with the black out. The root cause was a software glitch combined with human error combined with bad tree trimming. Before you type comments, you should get educated on the topic and quit blaming your government for every little thing you read about that annoys you.
Reply | Report Abuse | Link to thisYou honestly don't know what you're talking about with your references to "idiots" and "security systems". That had nothing to do with the blackout. Maybe you should run for office.
Reply | Report Abuse | Link to thisalso i dnt think tht this is a very good discussion hahahahaha
Reply | Report Abuse | Link to thiseven tho i have a twin tht thinks the same way u do dont mean i have to lyk it
Reply | Report Abuse | Link to thiseven though i am gayyy.......i think this is sooo stupid get a life u faggsss <3
Reply | Report Abuse | Link to thisi agree with John_in_PA hahaha u dnt kno wht ur tlkn bout u fool
Reply | Report Abuse | Link to thisget a lifeeeee!!!!!!!!!!
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