Maybe I’m being over simplistic here, but it seems to me that when a massive surge takes out the generators in the power grid, that they should be able to be back on line within a few minutes (with the possible exception of the first generator to take the lightning strike or whatever).
What am I missing here?
Your are right. You are being a little simplistic. There is a vast difference between interrupting a circuit carrying 10 A. and one carrying 2000 A.
And, of course, after the circuits are interrupted by breakers, the power to the grid is off and it takes time to get it restored.
The short answer is power stations need power to get started. The outage yesterday was a domino effect. Power stations were foreced to try to provide power for the rest of the grid, got overloaded and shut down, and couldn’t start up again, because they didn’t have power themselves.
IIRC, there are “circuit breakers” in transmission lines that are designed to trip so as to protect power plants. The power going out is done on purpose to protect more equipment from being damaged - just like a suge protector or circuit breaker.
This is the part I don’t understand.
From what I’ve seen in the newspapers so far, the Administration is aware that “the US has a third world transmission system”. OK, so what makes it “third world”? What needs to be done to make it “first world”? The figure reported in my newspaper was $150 billion to get the grid up to scratch.
Does anybody have a link to some information on this, say on the level of a Scientific American article? Or would it be easier to sneer at my simplistic question?
Anybody who has lived in a third world country would have serious issue with the idea that we have a third world elecctric grid.
The U.S. electrical grid is a bit too complex and powerful to be regulated by simple automatic circuit breakers. However, the system is supposed to isolate these power surges and there are 100 control centers around the U.S. whose job is to prevent problems from spreading further.
Why the surge that appears to have come out of Michigan (at last report) was not contained by the Ohio system is the mystery at this point. What has not been given much prominence by the news is that the Pennsylvania control center did exactly what it is supposed to do and kept the outage from spreading to the south and the lower midwest.
My wife, who is in the power industry, has been incensed by Bill Richardson appearing on every talk show saying that the U.S. has a third world grid. She says that it simply means that he has no idea what a third world grid is like. As one show properly said, businesses in third world countries wouldn’t have been knocked out like our did in this outage precisely because outages are so common there that every business has a backup generator.
Most of ours don’t need them: we have a first world power grid.
This is not true for many power stations. I won’t say “most”, because I don’t have a count, but I will say “many”, and to claim that power stations in general can’t start themselves is false.
Many coal and nuclear power plants have auxiliary diesel generators, auxiliary natural gas boilers, auxiliary oil burners, and so forth to provide startup power. Natural gas turbines need a very minimal amount of power to start up, even the HRSG combined cycle ones can get their power during simple-cycle operation to get the combined steam portion moving. Gas boilers need little power to start. If the plant needs to start up, there is often power available to do just that. There is a world of difference between now and 1965, where many plants did not have aux boilers and there were much, much fewer gas turbines. This is not universally true, of course, but it’s certainly not correct to say that this is why the units shut down. Most of them shut down due to load-trips, and didn’t start right back simply because of balancing the load on the grid, and because there are Procedures and Processes for bringing portions of the grid back online. Having personally sat in the rooms where these Procedures and Processes are implemented and dispatched, I can tell you that the electricity likely came on about as fast as it was going to. And, having spoken to the operators of one plant today which was knocked out, I can assure you that they had plenty of power available to start up whenever they were given the “go” from dispatch.
jiHymas, despite whatever bullshit the media is reporting, we do not have a “third world” power system. We have a slightly underfunded power system which must provide a HUGE amount of power over a HUGE geographic area, and it does the job really, really, well. The fact that large-scale non-weather related outages typically have many years between them attests to that fact.
The cause of the blackout isn’t clear at this stage. However, there are three possible scenarios:
1) Thermal overload.
This is the easiest to explain, but probably not what happened.
All of the transmission lines have limits on the current that they can carry. The current is constantly monitored, and if the limit is exceeded, say because of a fault (short circuit) on the line, circuit breakers at both ends of the line will open. The current that the line was carrying will be redistributed amongst the remaining lines.
The system is supposed to be operated in such a way that it can survive the loss of any transmission element. If it isn’t, the loss of one line can cause the overloading of another, which will then also trip, and so on.
2) Transient instability.
This is a bit more complicated. When there is a fault on a transmission line, the load on some generators is increased, whilst the load on others is reduced.
Normally, all of the generators spin at exactly the same speed, 3,600 rpm.
During the fault, generators with increased loads will begin to slow down a bit. The others will begin to speed up a bit. When the fault is removed by the circuit breakers on the transmisison line, the generators all have to return to the same speed. The slow ones speed up by drawing power from the faster ones, via the transmision lines that are still in service.
Again, the system is supposed to be operated in such a way that it can survive the re-synchronising of the generators.
3) Steady-state instability.
All of the generators and some transmission lines have control systems that monitor voltages, currents, and speeds. The control systems will respond in various ways. For example, a generator’s governor will respond to a slowing of the generator by increasing the boiler output or turbine fuel feed.
In some situations, a response from one control system can provoke an opposing response from another control system somewhere else. The first control system responds more strongly, which provokes an even bigger response from the second one, and so on. This can cause increasingly large oscillations in the current flows on transmission lines, until they begin to trip off.
And yet again, the system is supposed to be designed and operated in such a way that behaviour doesn’t occur.
jiHymas
Ummm…some politicians who are ready willing and able to try to sell the voting public on a tax hike that will go towards keeping things exactly the way they are (as far as the voting public would be able to tell insofar as it would be deployed towards repairing invisible infrastructures that seem to be working fine until they don’t).
And the electrical is just one of the systems in need of address. I’ve heard some scary things about the condition of water mains in many big cities, not to mention bridges and tunnels and whatnot.
The last time there was a big blackout (in the 70’s) it was caused by sort of a domino effect. The original fault caused an overload, which caused the next system over to fault trying to supply the extra current, and when that system faulted the next one went down, etc. The interaction between such large and complex power systems is very difficult to predict sometimes. There have been a lot of people in the power industry who have been saying that even though there have been improvements to the grid that it’s still vulnerable to the same sort of thing, but that has been debated for years. It’s a little early to say, but it looks like they could have been right.
The power systems do have automatically resetting breakers of sorts. They are called “reclosers.” If you’ve ever had an outtage where you are, you may notice that the reclosers will try and fix the problem after a few second, then after maybe 30 seconds, and then will give up. Reclosers are fairly simple devices and won’t help much in a system wide problem like the current event.
ahunter3 you have it right about other parts of various systems. on thursday a water main broke in philly and took down power for quite a bit of center city including two major hospitals. the main flooded a transformer station.
i’m wondering how old that main was. we have mains in sections of phila that are from the 1800’s. makes ya want to bring back all those work programs they had in the 30’s, and 40’s.
OK, so let’s forget the “third-world” rhetoric. I don’t really care how accurate it is. When I make a list of things that are utterly irrelevent to my life, politicians’ use of rhetoric is pretty near the top. I want to know what is actually being proposed, and why, and try to understand why I sat around in the dark yesterday evening and how much people are asking me to spend to lower the probability of that happening again.
A current Globe & Mail story, Joint task force investigates blackout states:
So Bush wants to “modernize” the electricity grid. Other news stories have said the administration has talked about it before.
Can someone please explain to me what he means by “modernize” and how much it will cost without getting all upset about the word “modernize”?
I won’t speak for exactly what “modernize” means in his context, but one thing I know for an absolute fact, that is true in many regions, is that more lines simply do need to be built. And building lines is expensive, mainly because of the siting, permitting, PR, paying off of landowners, and payoffs to “public interest groups”. There are many other things that can be done with respect to controls and interties and switching, but when it comes down to it, a major weak link in some areas is pure transmission capacity.
As I posted in yet another thread, EPRI estimates that it will take about $100 Billion or so. Other estimates run much higher.
Anthracite: In the power plant thread you indicated you have something like 20 GB of generator pictures…any chance I could take a look at some of these?
(I posted the same reply in the other thread just to ensure you see my reply, as your email address is not listed)
The DOE’s Electricity Advisory Board Subcommittee put out its Transmission Grid Solutions Report (pdf) in September 2002. At times, the report blurs engineering principles and free market rhetoric, but that’s the nature of the beast these days.
Cheney’s National Energy Policy report provides an overview of grid problems in the section titled America’s Energy Infrastructure (pdf). This is a less meaty article than the subcommittee’s report, but the graphics make it easier on the brain. Interestingly, Fig 7-2 of the report doesn’t show any transmission bottlenecks along the south shore of Lake Erie.
There was a blurb in the dead trees edition of USA Today (it doesn’t appear to be on-line) which mentioned that someone had developed a “superconducting surge protector” which might be able to prevent such an occurance from happening, but the device is still experimental and hasn’t been fully tested yet. It’s also pretty expensive to set up and maintain, since AFAIK, no one’s come up with a superconductor that works at even close to room temperature, so these units would have to be kept very cold, all the time, and you’d need a lot of them to protect the grid.
Thank you, Squink - you are a gentleman and a scholar - unless, of course, you are a lady and a scholar.
Most of these reports focus on the goal of building additional long-distance transmission capacity, which seems to me to be a secondary issue when considering the cascading effect of outages that occurred on the 14th. Yes, if a regional generator goes down, it makes sense that having excess long distance capacity will avoid blackout in that area as power is moved from regions with surplus, but very little is said in these reports about ensuring that the long-distance grid itself is robust enough to withstand outages on the long-distance grid itself, which is my primary concern in this thread.
If the “backbone” network is made ‘longer and thicker’, then it seems to me that, in the absence of action taken to ensure that it is more robust in its parts than the current system has been shown to be, then for each time I avoid a blackout due to one of Ontario’s generators going down, I will be blacked out by something in Tennessee (or wherever) going down and having repercussions over an enormous area, leaving me with more or less the same frequency of power loss. If I’ve got this wrong, I would appreciate being corrected.
The Transmission Grid Solutions Report cited above has a small section that appears relevent, Improving Infrastructure through Demand Response, Distributed Generation and Other Advanced Technologies, page 29, but is woefully lacking in details. I am particularly interested in their mention of “hardware and software applications that are used to create a ‘smart’ grid that can manage and adjust itself”. Problems in the Lake Erie loop? OK, Detroit goes down, Cleveland goes down, but Toronto and New York are unaffected as these regions seal off the problems (maybe with a short brown-out) and the problem, being smaller, is easier to fix.
If anyone has any further information on the “smart grid” concept - or is able to refute my reasoning above - I would greatly appreciate it.
And thanks again, Squink
A couple of poster have provided estimates of 100-150 billion dollars to make necessary improvements in the electrical grid. I expect that we’ll be forced to pay some sort of $5-10 monthly fee on top of our electric bills for a “Grid Improvement Fund”.
It reminds me of the Aviation Trust Fund, which gets billions each year from a 9% tax on airline tickets and taxes on aviation fuel. The money was supposed to be used to improve airports, particularly improve the air traffic control system, which was described as insufficient and obsolete (sound familar?). But my understanding is the government spent little of the money, preferring instead to use the money to cover the general deficit.