Re: Nuclear Reactors & Blackout

["Robert I. Eachus" <rieachus@attbi.com>]

Dmytry Lavrov wrote:

> Heh,if net are overloaded,SUPPLIES are diconnected???
> Why not disconnect some towns to save network (as in xUSSR "-)??
> What's , USA network are so simple and  based on plants connected in
> parallel ,works as one plant,and towns in parallel,works as one
> consumer? If so,it's simply idiotism.
> 
> There is so simple to make non-buggy (by overloading) network:
> let's each supply provides energy for nearest towns(let's call it
> "sector"),and maximal power of towns = power of supply.When supply
> aren't 100% used,some energy are transmitted to other regions.If supply
> are overloaded by local towns,it's only consumes energy from another
> plants.There are buffers between sectors that newer overlod plants,only
> transmits as many energy as sector aren't uses.  And if one sector are
> overloaded,when it's overloaded more than can get from another
> sectors,some non-critical pards of the sector are disconnected,and other
> sectors aren't overloaded. In Russia,there are as many short circuits a
> year,and we should have blackouts every week if network work same way as
> in USA.

I hate to say it, but simple, straightforward, and unworkable.  The 
problem is best described as the distributed properties of the network. 
  All of the interactions between generating stations and power 
consumers occur at transmission line speeds. (Which are significantly 
slower that the speed of light in a vacuum, but not enough to help. 
Call it 1/2 to 3/4 c depending on the type of line.)  When you detect an 
overload at a generator, even if you could break a circut and shed some 
local load, the overload "in the pipe" of the transmission line may be 
enough to burn out the generator.

Of course, if you have studied, or worked with, high voltage power 
transmission, you know that breaking the circut and making it stick is a 
non-trivial operation. In the 1965 blackout, NYC was drawing 3 Gigawatts 
from the TVA.  This was being distributed over the PJM interconnect, but 
they needed to be able to break the circut if something like this 
happens.  Imagine a twenty foot high circular tank about 4 feet in 
diameter filled with oil and with baffles and a blowout panel on top. 
(The baffles are designed to catch as much oil as possible while letting 
the gasses and plasma out.)  Through this tank bottom to top pass four 
1/2" by 3" copper bars arranged in a square.  Fill the tank with oil, 
and suspend a 1/2 pound block of C4 in the center of the hollow square, 
about 5 feet from the bottom.  That is your basic 1 Gigawatt breaker. 
(Actually rated at 5,000 amps load at 330 KV.)  There were three of 
these sitting near the border between Pennsylvania and New York State.

One of the power engineering magazines had a picture of one being 
tested, and about a year later, a picture of the actual devices firing. 
  (No big trick, they had a TV camera showing these breakers in the PJM 
interconnect control room, and a movie camera triggered when the arming 
circut blew the breakers.)  I may have told this story before, but I 
lost a bet with my father over the day the blackout would happen, my 
brother was in the pool as well, but we had all picked days that week 
over a month before.  I won't go into all of the details, but ConEd had 
two big nuclear plants down for refueling, a judge had some coal fired 
plants owned by the Transit Authority shut down for pollution reasons, 
and it was the week after daylight savings ended.

So think of the power from Naigra Falls flowing through transmission 
lines to NYC as an express train.  Throwing any breaker along the way 
converts it into a runaway train that is going to destroy whatever it 
dead-ends into.  You have to have something to sacrifice at the end of 
the line, and deadending into houses or most commercial loads is going 
to cause disasters. You have to have some breakers like the ones I 
described above that can take the load and terminate it.  The arcing 
lasted for milliseconds, and the total energy quenched was over 100 
times the explosive energy of the C4.  PJM shed load at Conowingo and 
elsewhere until the TVA could back off what they were delivering, and so 
there were no major power failures south of Trenton, NJ.

The instantaneous demand from New York when those breakers went was 3 
million amps.  (Yes, that is an instantaneous demand equivalent to 
several hundred nuclear power plants.  The problem as I said was that 
the Lake Erie Loop can become an amplifier.  The pulse that flowed down 
the line became a peak followed by a trough that reversed voltage.) As 
long as you refuse to run interconnects in or near amplifying states, 
the normal procedures are fine.  But once you have an actively 
amplifying network you are up the creek.

Right now they are looking at three transmission lines in Ohio that shut 
down a couple of hours before the main event as the trigger.  My bet is 
that they will find that those failures set the stage, and the next 
sneeze, even bringing one of those lines back into operation, caused the 
actual event.  The Lake Erie Loop mentioned above consists of 
transmission lines both above and below Lake Erie, and yes, they do form 
a loop.  The direction of power transmission in this loop reversed just 
before the blackout...

-- 
                                        Robert I. Eachus

"As far as I'm concerned, war always means failure." -- Jacques Chirac, 
President of France
"As far as France is concerned, you're right." -- Rush Limbaugh