Power grid structure

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In a previous post (Power Plant Rumor) Ed discussed the possibility of a Western power plant going offline due to Y2K and/or terrorist attacks.

As I keep seeing these various rumors and discussions I keep wondering about the power grid layout itself and about the sectioning or isolating of the grid(s) should there be major failures.

For my beneift, and I suspect for others as well, can someone who has knowledge of the grid layout either describe or point me to online descriptions of how the grid is sectioned, what states are served by each and any known plans for regionalizing areas of the grid should problems occur?

Will certain faults in one area be prevented from affecting the whole grid? Can anyone describe (factually) about what could happen or how the power consortiums may handle these events?

Thanks,

Charlie

-- Charlie (chicks@ix.netcom.com), December 02, 1999

Answers

Somewhere there are maps of the different grids. I just remember that in the big blackout of ??? Aug. 1996 ??? 14 western states and parts of Canada and Mexico went down. Major victory for the Squirrel King.

-- Linda (lwmb@psln.com), December 02, 1999.

People have been saying they might island. Good for the cities, bad for some of the rurals, who will then lose power. Ought to keep the cities up though. That's important for many reasons, including lots of old, vulnerable folks and the economy.

-- Mara (MaraWayne@aol.com), December 02, 1999.

Somewhere on the web there is a downloadable PDF map of the grid. It might be in very old threads on this forum or Roliegh's. I looked through my files and cannot locate...sorry. If someone knows the location of the grid map please post here, as I'd like to gander again myself.

-- Lisa (lisa_dawn@yahoo.com), December 02, 1999.

Maybe Homer can check this out for us. He seems to be the "information guru". If he can't find it,then....

-- Familyman (prepare@home.com), December 02, 1999.

Ok, here we go.

Sorry but Im not going to post an outline of the grid. Dont want to give anyone ideas!

In essence all of the western states and the western part of Canada are served by the Western Grid and Eastern North America by the Eastern Grid. But as a practical matter power from Maine doesnt make it to Florida. Not true in the Western US where power from BC or the Columbia River power system does make it to California and the Southwest. The Eastern Grid is very stiff, the West less so. In the Eastern Grid there are numerous operating groups that each controls a portion of it. You can find these by looking at NERCs web site. The Western Grid is served by one operating group.

The Grid (or grids actually) are sectioned in various ways. First each line is protected by relays or fuses. A fault on a line should only cause that line to trip. Usually when bad things happen its because of multiple failures, and at times of heavy loading. What causes the Grids to separate is usually either a swing or a cascading collapse in voltage. Then the various parts island. The islands however are quite large. They are not city size, or county sized. Some even run to several states. Sorry Mara it doesnt work quite the way you think it does.

Charlie I would suggest you look in the archived threads for Malcolm Taylors Electricity 101. It might help you understand it more.

-- The Engineer (The Engineer@tech.com), December 02, 1999.



I found a map at this address. NERC does have useful information sometimes.

http://www.nerc.com/regional/

-- Margaret J (janssm@aol.com), December 02, 1999.


Most of Texas, as usual (?), is separated from both east and west sections.

Also, the "grid" as we generally refer to it, includes more than "just" these very high voltage lines cross-connecting regions of the country and area power suppliers.

"The Grid" is usually (though incorrectly) used to refer to the local high voltage distribution system in each region, and to the sub-station and major control stations/center of each utility. After all, the real threat to the electric distribution system comed from the fact that "you can't store electricity" - it MUST be immediately generated, immediately linked to the local and national "grids", and immediately distributed to each user - or the power is out.

Unlike almost all other systems, power has no reserves or delays, and cannot be distributed until/unless all intermediate centers are able to control their own local grids - it's not just the power plants, just the control centers, or just the utility "billing" and "administrative" systems - it's all of them together that must work correctly for the utilities to remain in business profitable.

If fuel were avalable , they (the power plants) could possibly keep generating electricty in the absence of other y2k-induced problems, but eventually, the people supplying them fuel and parts would begin demanding payment to meet their own bills. Though admittedly, if billing was "lost" completely not too many users would complain until they had to pay exhorbitant power statements....it's the people owed money and the stockholders who would first complain if bills were screwed up....

-- Robert A. Cook, PE (Marietta, GA) (cook.r@csaatl.com), December 02, 1999.




-- Hillbilly (Hillbilly@possum.creek), December 02, 1999.

Billy, Where did you get that map from? A URL please? thanks!

-- Ken Seger (kenseger@earthlink.net), December 02, 1999.

Interesting map coutesy of a link via: y2ksafeminnesota

US Power Grid

-- hiding in plain (sight@edge. of no-where), December 02, 1999.



BTW: the map that hillbilly posted came from the link -

http://www.nerc.com/regional/

that Margaret J had posted above his.

-- hiding in plain (sight@edge. of no-where), December 02, 1999.


Margaret J: Do you like to mudwrestle?

-- King of Spain (madrid@aol.cum), December 02, 1999.

Uh, guys and gals, thats not a picture of the grid...thats the NERC regional council areas of responsibility...

Regards,

-- FactFinder (FactFinder@bzn.com), December 02, 1999.


hey Hillbilly - can you grab and post here the image map of the grid itself off of the link I posted ?

or teach me how and I'll do it. :-)

-- hiding in plain (sight@edge. of no-where), December 02, 1999.


THE NORTH AMERICAN POWER GRID:

Public thanks to Dog Gone for the quick tutorial. :-)

-- hiding in plain (sight@edge. of no-where), December 02, 1999.



Oops. blew it teach ... hanging head in shame... hopefully will get it right this time.

THE NORTH AMERICAN POWER GRID:



-- hiding in plain (sight@edge. of no-where), December 02, 1999.


Third time is a charm .... RIGHT?



-- hiding in plain (sight@edge. of no-where), December 02, 1999.


Whataya know ... :-) It worked!

Thanks Dog Gone. Took me three tries, but I got it! :-)

-- hiding in plain (sight@edge. of no-where), December 02, 1999.


Okay - quick question here.

You see all the little black lines? Each is a high voltage transmission "system" - has the wires and towers (of course) but also controllers, stations and substations to drop voltage to the "local grids" at each utility and EMC, sensors, monitors, remote central control stations, and "cross-connects" to other high voltage "systems". (Obviously, at least one cross-connect at each "end" of each line where it touchs the next high systems, but usually more. Hookups as well at each power plant where the plant taps in the distribution systems.)

Now - what testing have you heard of about all these functions? Let's assume the power plants are y2k-compliant (as promised by the Clintons' administration)....let's assume each of the 4000-odd power plants in the US have been taken off-line, completely remediated, and date-advanced and then re-tested, then re-connected to the system. Now, what system-wide testing has been done on the distribution system? Who did it? Who audited it? When did they test how they control the grid?

-- Robert A. Cook, PE (Marietta, GA) (cook.r@csaatl.com), December 03, 1999.


Bob,

Not all those lines are high voltage lines. There arent that many in the US. What you are seeing is the main grid, sub-grid and probably some of the distribution.

Most distribution is still electromechanical. You control it by sending some out to close a breaker or replace a fuse. Its a mistake to think that every line has controllers, sensor, monitors, etc. on it. The big stations have all of that, and more. But as you go down in voltage the amount of monitoring and remote reporting also goes down. The amount of equipment in a main grid 500 KV station is quite different from that in distribution station. Some Utilities have modernized and put SCADA in all of their subs. A lot havent. Its expensive to do.

You cant really end to end test something with fuses on it. The mistake that you make is thinking that the Grid is somehow controlled by software every step of the way. It isnt. I think one of the misunderstandings about power is thinking it is far more automated and controlled (every step of the way) then it really is. I refer you to Dick Mills excellent columns in Westergaard, as well as Malcolm Taylors writings on this forum.

-- The Engineer (The Engineer@tech.com), December 03, 1999.


Granted, most certainly.

If all the world's a stage, this particular stage is extremely complex and has many levels - most (almost all) hidden from public view and awareness. Almost all - also - far beyond what even the previous excellent briefings can cover to a non-techincal audience.

My point remains - like my own EMC claims - and probably claims correctly, for that matter - that there are several vunerable points in electric distribution: the power plants' suppliers and venders - threatened if extreme troubles occur for longer periods, probably okay in the short term - even if utilities can't pay their bills; the power plants themselves: supposedly remediated, but only self-reported for fossil plants, and no publicly-announced testing (outside of Ontario Hydro and a few hydro plants). Power plants can be remediated, but may face troubles from isolated, unforseen processes not exposed during system testing..... fossil plants have few (if any) backup, and limited black-start features.

Utilities themselves face addtional troubles on the business side: payrolls, accounting, taxes, receipts, receiving payments, etc from any other infrastructure problems - including satellites, telephones, remote cities, local city services, etc.

Nuclear plants are reported compliant, and have been audited - but they could face control difficulties if the grid is unstable: the power plants would be repeated tripped off if the grid is unstable.

The major grid points, then the minor and then the distribution points, as you point out, are a mix of mechanical devices, mechanical and electrical devices with remote control, local controls, and manual controls. The small gear can be successfully operated manually, if regional control is properly coordinated to avoid trouble at other manual substations. Higher up - remote controls, or direct control remote stations (radio/satellite/telephone) is essential in manageing the opening/closing of the systems.

As noted - my local EMC claims compliance and described its manaul work-arounds, its contingency pans, and its preparations such as emergency generators; all the while repeatedly also bosting of its "automated" central stations and central control panels.....which we hope also run properly. And, of course, my EMC only purchases power, it cannot generate it.

The vunerablities of the distribution system under manual control are the reason I expect intermittent service - frequently dropping in and out, rather than long-term blackouts. (Assuming most of the power plants are as well-fixed as they claim.)

-- Robert A. Cook, PE (Marietta, GA) (cook.r@csaatl.com), December 03, 1999.


Bob,

Yes and No. You are right to say that at the higher levels its operated remotely, most of the time. But it can be operated locally if need be.

It has to be from just from a safety standpoint. In order to work on a line (assuming you arent working hot ) there has to be a visible air gap. That means the disconnects have to be opened and locked opened. That mean a human has to go out to the station, unlock the disconnect, open it, lock it open. If any grounding switches have to be closed they are locked close. Every breaker that I ever have worked on has a manual trip and close both in the breaker and in the substation. Some of the new stations do have computers in them and have done away with the manual switch in the sub. However it still exists in the breaker cabinets. And there is always the clip-clip! 

A lot of times when work is being done in a substation it is taken off of SCADA and an operator is there to operate it manually. Also a number of small transformers have what is called no load tap changers. To change a tap the bank has to be taken out of service and the tap changed moved manually. Most of the voltage regulators do it automatically on voltage control and most of the really big ones are remotely controlled.

Also please note that the equipment isnt really operated that much. Unlike your house where you turn on a light in a room and then turn it off when you leave the room the switches on the gird are for the most part always closed. There are exceptions where lines are takend out late at night for voltage control. When a fault occurs the switching is automatic and local. Most of the time the reclosing is the same. You really only need a lot of the remote control when the lines go to lock out and you have to put them back in service. Then SCADA saves you windshield time. But it can be done without it. All stations have synch check meters in them.

This is even more true at the distribution level. The line to your house is always hot. Quite frankly unless there is a fault on the line feeding your house or the line feeding it there should be no droping out and coming back. Any worry would be more the opposite. If generating plants or large loads had trouble there could be swings. Swings are really dangerous because they lead to system breakups. Hopefully there wont be to many big loads deciding to turn everything off at 11:55 PM and then turning everything back on at 12:05 in your neighborhood. Then you would have problems.

-- The Engineer (The Engineer@tech.com), December 03, 1999.


Exact - the fact that these systems aren't operated routinely (in manual) is why "remote-manual-control-through-operators-on-radios" - if needed when remote-automatic control is lost - is tricky and not as reliable as current conditions allow.

We hope that remote operators aren't required - failure, after all, isn't guaranteed, only likely if remediation wasn't 100% successful. That's the reason for my "insistance" on 100% drills on all shifts at all stations - to exercise those kind of rarely done procedures and infrequent operations...just because a thing "can be done" doesn't by any means reliably assure customers that "it will be done" when tried the first time in the real world.

Again - your comments show why I expect irregular and unpredictable power failures are more likely than long-term blackouts.

---...---...

Unfortunately, even a short blackout screws up most industrial, commercial, retailing, and distribution processes very thoroughly and expensively - leading to (and contributing to the general loss of prodcutivity in early 2000 that will exaggerate the expected recession - even if overseas distribution, manufactoring, mining, and raw material shipping can keep up through the troubles ahead.

-- Robert A. Cook, PE (Marietta, GA) (cook.r@csaatl.com), December 03, 1999.


Bob,

I think there is a misunderstanding.

Operating on manual is done on a regular basis. When a crew goes out to a substation to install new equipment or replace existing equipment an operator is there to do the switching. It is not done by SCADA. The equipment has to be tagged after a clearance is given. You need a person to do this. Ditto when a line crew goes out to work on a line. We have lots of line crews. They are out every day. Large systems are in need of constant looking after, even with a four year maintenance cycle. You have to repair what breaks and do your regular maintenance. We do not pay our electricians, line crews, communications people, relay people, and operators to sit around until something doesnt work. They are out there every day doing maintenance. With several thousand breakers, thousands of relays, etc. there is enough to keep them busy.

When I said the equipment isnt operated every day I meant that a lot of breakers are not opened and closed every day. Most of the equipment sits quiescent most of the time. However there are faults on the system every day from trees, lightning, and yes squirrels. Operators visit stations on a regular basis to look in and see what is going on. Some day it may all be on a web cam but we arent there yet.

True we dont have as many operators as before. But in the past many stations where manned 24\7 and most of the time the operator sat around a lot. Now they are on the go quite a bit more and do more operating then before. The operators go through regularly schedule refresher courses and on top of that each station has Standing Operating Orders which are reviewed regularly and clearly define how the station is to be operated.

-- The Engineer (The Engineer@tech.com), December 03, 1999.


Thinking too of what you just wrote - we may not have any choice about the "big industrial loads" dropping off as they reach different problems in controlling, maintaining, and measuring different on-going processes - of course, some are going to measure local time, GMT, GPS time, etc. Some won't trip at all - but may fail unexpectedly do to other causes - even on a holiday weekend, there are certain things (like steel mills and refineries) that simply can't shutdown - at least, not without a lot of extra expense and lost money trying to restart.

Nothing is assured - now, it remains at best, only guesses - and all guesses - the entire analytical process, in fact - are heavily influenced by whether one expects major problems, minor problems, or simply hopes there are no problems. Certainly - no one can claim any system-wide test (other than what Ontario Hydro did) that would indicate actual results....

The fed's are looking (and talking) only at the first tier - only at banks (as a stand-alone entitiy); only at the power plants (based on what NERC has told the power plants to tell NERC!); and only at the federal government level for the critical systems (based on only self-reporting from those top-level administrators who report to the White House to find out what to report - and when to report it.)

There have been no government-wide tests run between departments and agencies - health care, Social Security, Vet's Dept, DOD, .... , the list if affected systems remains, at best, only partially remediated and un-checked.

The system remains at risk.

I wish we could isolate Hawaii (or NZ ?) and force them to test everything - ---- I wonder if they would mind?

-- Robert A. Cook, PE (Marietta, GA) (cook.r@csaatl.com), December 03, 1999.


You will have to ask Malcolm about NZ.

I'll be more then happy to go there or to HI to "help out".

-- The Engineer (The Engineer@tech.com), December 03, 1999.


Robert, You said "I wish we could isolate Hawaii (or NZ ?) and force them to test everything - ---- I wonder if they would mind?"

We will do that for you. NZ are scheduling a complete nationwide test of EVERYTHING beginning at around 11:00 UCT on Dec 31st. :-)

Malcolm

-- Malcolm Taylor (taylorm@es.co.nz), December 03, 1999.


Tell Alabama - they have their test scheduled for February 30th, 2001. 8<)

-- Robert A. Cook, PE (Marietta, GA) (cook.r@csaatl.com), December 03, 1999.

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