Big Blackout. What Happened II 7

[jghrist]

I agree that the old "Big Blackout. What Happened" thread has become unwieldy. A very informative article was just posted on the IEEE Spectrum website.

http://www.spectrum.ieee.org/WEBONLY/special/aug03/black03.html

 

[Skogsgurra]

Yes, jghrist.

I was not even able to load it the last week. My tired old copper wire 50 kbits/s modem (living right in the middle of the Nordic forest) was simply too slow. I think that a second thread is just right. Could someone with a faster internet connection (and a lot of patience) give us a summary of the discussions in Big Blackout One? It would be nice to know what the outcome - if any - was.

Gunnar Englund

 

[alehman]

Summary of recent subjects and links from the previous thread. I probably missed a few.

Possibility of terror attacks taking down the grid

http://www.washtimes.com/upi-breaking/20030904-070049-7423r.htm

Analysis is power flows leading up to the outage

http://www.nautilus.org/energy/grid/papers/bickel.pdf

Everybody has a cause to promote

http://www.evworld.com/databases/storybuilder.cfm?storyid=567

Congressional testimony by FirstEnergy relating to computer problems

http://www.energycentral.com/sections/news/nw_article.cfm?id=4118550

http://asia.reuters.com/newsArticle.jhtml?type=topNews&storyID=3392866

Discussions of possibility of new techologies being able to avert a wide blackout.

Good article on a 2002 blackout in Mexico

http://www.selinc.com/techpprs/6141.pdf

How long should the investigation take?
NERC generation projections for various ISO's.
Cost to upgrade the transmission grid and priorities for the upgrade.

http://pro.energycentral.com/professional/news/power/news_article.cfm?id=4122003

What really is good operating practice?

http://www.computer.org/proceedings/hicss/1874/track2/187420065babs.htm

Communication between ISO's
Start new thread for technical level discussion?

 

[lengould]

This describes a dispute btw. Dave Flanagan, a spokesman for the state Public Service Commission, and representatives from the American Lung Association, the New York Public Interest Research Group and four other organizations who called for a better transmission system, better planning, more conservation and a shake-up of the state's deregulated power system.

http://www.timesunion.com/AspStorie...&category=BUSINESS&BCCode=&newsdate=9/11/2003

This is the sort of thing I was on about before re. "huge investments" questionable.

I really enjoyed the article found by spitfire. Star there. I'll re-link it here for any who have not seen it yet.

http://www.computer.org/proceedings/hicss/1874/track2/187420065babs.htm

Been chewing on it all day, and come to the conclusion I disagree with part of the concept of the article. The authors definitely deserve praise for having discovered the mathematical relationship described, but I can't agree with the presentation of the grid/outage/improvements/cost relationship as comparable to the forest/fire/firefighting/cost model. I'll grant it is a useful analogy but could lead to errors (IMHO) in that the fire supression crews have no control over where, when, or how nature will add more fuel to the forest, whereas the process of adding more complexity to the grid is in theory completely within the reach of control by aware actors.

The tone of the article implies there is a "fundamental" need for the grids studied to react in the manner discovered, whereas I think that a responsible grid management body controlling adds and border interactions etc "could" operate any grid in a way that the relationship discovered would not apply or be so well supressed as to be irrelevant.

But, then again. Agree / disagree?

 

[SphincterBoy]

Not one article posted details "exactly" what caused the blackout, just the system(s) response(s) and other ramifications.

An NBC newsreporter uncovered the fact that tree trimmers were trimming trees near the FirstEnergy 345 kV lines in Ohio. Another person who happened to see them in the area, heard several loud explosions.

This person drove down to where the trimmers were at near the 345 kV line, and asked them if they hit the power lines.

They responded "No".

For some odd reason, I think this is the most likely cause, based on my experience with linemen and tree trimmers. Some will 'fess up', others will not, when screwups occur.

A phase-to-ground fault trips numerous circuit breakers on each end of the line, destabilizing the system, and cascading into the other systems.

 

[lengould]

Is it true that one short circuit event on one 345 kv line "could/should" blackout 50 million people 24 hrs? I know, everything at peak, hot august afternoon, Ont. generation was under spec (late re-starting some mothballed reactors).

If so, and crews are as described above, then should not allow them to operate at seasonal peak time.

re: my previous criticism of article found by spitfire, I take half of it back. It occurs to me that if de-regulation and economics come to the point where every (second) home and store instals CHP generation, and each using the distribution for leveling instead of installed storage, then the system does become like a forest with no control of adds / changes. Several consequences.

a) Entire electric grid stability becomes dependent on gas/fuel distribution system. Very reliable to now, but what about when Nat. gas shortages start? One remote region loosing fuel supply would be like one 345kv line getting shorted.

b) If grid only managing e.g. 50% of generation/load and required to satisfy all connected requirements, becomes far less stable than it is now.

One solution will be to refuse to allow CHP generation to use the grid system as a battery, at least for free. The only way systems like a) most solar PV b) JXCrystals 1.1kw gas fueld thermoPV c) Microgen Inc 1.1kw Stirling engine

http://www.microgendirect.com/products_how.html

all depend on the grid to be their "battery". They intend to generate a continuous average rate of power and have the grid absorb unneeded power and return it (free) when the user wants. I think this sort of free ride system should not be allowed to send power back through the meter into the grid until issues like are raised in the article above are sorted out.

 

[jstickley]

lengould --

Yes. A single fault can trigger a cascading event. However, the system must be operating outside of established reliability criteria for this to occur. If you're interested in the rules the industry lives by for operating and planning the system, see the NERC Operating Manual (

http://www.nerc.com/~oc/opermanl.html).

That being said, don't point the finger at one single outage as the cause -- remember that there were a large number of outages (both generation and transmission) that occurred in the time period leading up to the blackout. The combined effect of these outages is, in all likelihood, the cause (note that we still need to be patient and wait for the report before drawing conclusions -- none of us have complete information on the event, to my knowledge).

Regarding tree-trimming, don't forget that this is one of our most important reliability practices. Keeping right-of-way clear is essential to ensuring that transmission lines can operate at their rated capabilities. I'd much rather have a crew clear a danger tree during the peak period than to operate with crossed-fingers, hoping that the known danger tree does not cause an outage (or worse, not knowing it exists at all). As with any maintenance, there's always risk -- the key is whether all precautions are being taken to minimize that risk.

 

[jstickley]

NERC has posted a sequence of events of the blackout on their website:

ftp://

http://www.nerc.com/pub/sys/all_updl/docs/pressrel/BlackoutSummary-Draft-6b.pdf

I haven't reviewed this yet, but it should be interesting information.

 

[SidiropoulosM]

The new information from NERC makes specific mention of a voltage collapse scenario which seems very plausible and which we were among the first to advocate here on eng-tips, on Blackout thread I.

 

[jstickley]

Makes sense to have a link to that thread here too, in case anyone wants quick reference: thread238-67677