Posted on 08/17/2003 7:33:34 AM PDT by Brian S
Ohio Lines Failed Before Blackout By RICHARD PÉREZ-PEÑA
The events that led to Thursday's blackout began when several high-voltage transmission lines near Cleveland failed, investigators said yesterday. The utility that owns the lines said an alarm that should have alerted controllers to the shutdowns also failed.
The line failures — including one triggered by contact with a tree — began at 3:06 p.m., 65 minutes before a wide swath of the United States and Canada lost power, said Michehl R. Gent, president of the North American Electric Reliability Council, the power industry group that is investigating the blackout.
It is not clear whether the problem with the alarm delayed action by the utility, FirstEnergy Corporation, or the consortium that controls the regional grid, the Midwest Independent System Operator.
The council's first detailed timeline for the initial system failures, which it released yesterday, also does not answer what many people in the power industry say is a more pressing question: how a failure in one place, no matter how big, could have spread catastrophically to other regions, overwhelming mechanisms designed to halt such a spread.
But Mr. Gent said he was prepared to say for the first time, "We're confident this started in Ohio."
The first failure hit a 345-kilovolt transmission line near Cleveland, for reasons that remain unknown. Ordinarily, that would have no effect on service because the load would be transferred to other lines nearby.
But adding power to a line makes it heat up, expand and sag. Twenty-six minutes after the first line failed, Mr. Gent said, a second 345-kilovolt line in the same area, probably one helping to carry the load from the first failed line, sagged into a tree, causing it to shut down. Trees near transmission lines are supposed to be cut back to prevent such accidents.
With the remaining grid in northern Ohio becoming more strained, three more 345-kilovolt lines in the area failed, at 3:41, 3:46 and 4:06 p.m. Over the next five minutes, systems throughout the Eastern United States and Canada began to see huge swings in voltage and in the direction of power flow, and more lines went down. Power plants shut themselves off to protect their equipment from harmful fluctuations in the flow of electricity, first in Ohio, then Michigan, then New York, then Ontario. At 4:11, the blackout began.
Of the first five lines to fail, four belong to FirstEnergy. Based in Akron, it is one of the nation's biggest utilities, with millions of customers in Ohio, Pennsylvania and New Jersey. The fourth of the five lines to go down belongs to American Electric Power, another major power company.
FirstEnergy released a statement last night saying that "its computerized system for monitoring and controlling its transmission and generation system was operating, but the alarm screen function was not." A company official confirmed that this meant that an alarm system that was supposed to alert controllers did not do so. It was not clear whether the system, besides flashing messages on control-room computer screens, also included an audible alarm. The official would not provide additional details, and no one from the Midwest energy consortium could be reached for comment.
Even without the alarm, "it's inconceivable to me that the utility and the I.S.O. wouldn't know what was going on, and they probably ought to have been able to do something about it, to stop it from spreading," said Karl E. Stahlkopf, senior vice president of the Hawaiian Electric Company and a former vice president of the Electric Power Research Institute in Palo Alto, Calif.
He said there is a precedent for grid managers failing to stop a cascading series of transmission lines, which then spread from one region to another, notably the 1996 blackout that hit most of the West Coast. But since then, the industry has tightened many of its operating rules, including those requiring systems to keep their neighbors apprised of their problems.
Business leaders, electric power experts and government officials have warned for years that the nation's transmission grid is seriously strained, especially in the Midwest. Some of those warnings have focused on Ohio.
During the same time period, companies that are large consumers of electricity have complained of a rapid rise in the number of times that transmission bottlenecks have led regulators to restrict the flow of power around the region. A report by a group called Industrial Energy Users-Ohio cited a nearly fivefold rise in such incidents between 1999 and 2000, and called for changes in the system.
The transmission lines in the Cleveland area are part of what the power industry calls the Lake Erie Loop, a ring of lines in the United States and Canada that have become a sort of electricity interstate, moving vast amounts of power from one state to another. In assessments of the reliability of the national grid, Mr. Gent told reporters Friday, that loop "has always been a big, big problem" in part because it is so heavily used.
While Mr. Gent put the start of the chain of events at 3:06 p.m. Thursday, there were indications that trouble might have started earlier.
FirstEnergy said in its statement that on Thursday, before the lines failed, a coal-burning power plant it owns in Ohio, Eastlake Unit 5, shut itself off, for reasons that are not clear. And readings taken by a Wisconsin company that monitors the flow of electricity for its commercial customers suggest that the problems in Ohio might have started the day before the blackout. Sensors used by the company, SoftSwitching Technologies, show that its customers in Ohio experienced frequent swings in voltage starting after 3 p.m. on Wednesday and continuing into Thursday, according to a database accessible on the company's Web site.
The readings show power lines dropping below their usual operating voltage for periods ranging from a few seconds to several minutes, while the flow to consumers in other parts of the country remained far more stable. Small voltage swings are not uncommon, but they are usually very mild and brief. These were sharper, more prolonged and much more numerous than usual, and the database shows that some customers lost power completely on Wednesday night.
"Instability in the voltage is something you really worry about," Mr. Stahlkopf said. "In the '96 outages in California, we had very large voltage swings, which caused relays to trip, which caused plants to go offline, which caused blackouts."
The company's database also shows Ohio consumers repeatedly experiencing a much rarer condition: voltage running higher than normal for a minute or more, from mid-June through late July. Several experts said that such "overvoltage" can indicate systemic trouble in the local grid, and that if severe enough, it can damage power systems. But they also cautioned that it is not clear whether any of these patterns were more widespread, or had anything to do with the blackout.
Blackouts are often caused by summer heat, as peak demand strains the system and equipment overheats. Mr. Gent and others have ruled that out in this case, noting that neither temperatures nor demand were terribly high on Thursday.
But a report by the Electric Power Research Institute proposes that warm weather could have played an important role, though an indirect one. When a problem causes voltage to drop, a lamp or a television might dim, and when the voltage rises again, the appliance returns to normal without a notable increase in power consumption.
Air-conditioners, though, work differently, and they account for a huge proportion of summer electricity use. Air-conditioners and some other devices, including many elevators, have electric motors that slow down when voltage drops. The motor's response is to draw much more power, trying to resume its usual speed.
The research institute's report proposes that that can lead to damaging swings in voltage, and turn a moderate voltage drop into a much steeper one that causes equipment to fail.
Then you and I are in a similar boat. I worked originally for Cleveland Electric Illuminating company in a variety of jobs. In 1993, I got promoted to system dispatcher. In those days, we ran the system with but a handful of knowledgeable (and not so knowledgeable) people and it worked fine. We were also vertically integrated from plant to customer. Then, along came somebody that decided that the transmission grid should become a common carrier. That was the first problem.
In 1997, we merged with Ohio Edison to form FirstEnergy Corp. I wasn't real happy with the merger, but I was attending college part time and decided to stick it out. There were a multitude of reasons for my eventually leaving, but a good part of it was that they were taking big chances with the grid. In 1999, on a hot summer day, I witnessed the wheeling of huge amounts of power from AEP up through our grid and into Michigan. I had a 2000 amp 345 kv line loaded at 2000 amps all day. System voltage was in the dumps, and I recall spending about 15 minutes on the phone with MTD corp's VP of operations trying to explain why his voltage was so low that he could not operate the motors in his plant. It was obvious that we were in violation of NERC policy, since there was no contingency for a line tripping or generator loss.
Right after noon, the manager came out and basically told us that if any 345 kv line tripped, we were to dump a specific amount of load ASAP. I don't know about you, but I find that to be a rather risky proposal. It also doesn't sit well with me to put my own customers at risk so that another utility can use my lines to pass power to a third party.
I got my degree in 1999, and tried several times to take different positions within FirstEnergy, but I was pretty much locked in to dispatching. The final straw was when the passed me up for a foreman's job and gave it to a laid-off person that had never worked in a company substation in his life.
Oh yeah, in Cleveland, we never had a tree get into transmission - only distribution where it affected relatively few customers. At FirstEnergy, lines in southern and central Ohio were always tripping in the summer due to tree contact.
Sorry for the long-winded post.
Power lines and any conductor like trees don't mix.
Now if the Internet over Power Lines had been deployed as some wish, the Net would have gone down as well.
Eastlake unit 5 is a little temperamental, and I suspect that it doesn't get the maintenance it used to get when CEI ran the place. I wish I could talk to the old operators there - they were great to work with.
While it is probably cost-prohibitive to keep all lines clear of all trees at all times, it shouldn't be hard to keep major transmission lines cleared - they are vital links.
If you knew FirstEnergy, you'd be surprised it didn't happen a few years ago...
I learned a lot from watching the various crafts at Diablo Canyon. Those guys (and a few gals) were the best there was. I was young and foolish back in the 70s. I didn't realize that I was helping to build a shrine.
While I've not ruled out foul play, I think it is more likely that it was just a bungled-up system. From what I've read so far, that Lake Erie area seemed like an accident waiting to happen. Too many different systems all tied together up there - all with different agendas.
I can't stand to watch TV on this, either. I've sent several flaming E-mails to Fox, but they just keep repeating the same stupid mistakes.
The truth will come out, but not on TV. You will read it right here on FR, eventually.
Interesting about the union connection. One more thing that you will never hear on TV.
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