
Black Start - anthonyb
http://en.wikipedia.org/wiki/Black_start
======
ChuckMcM
This was one of the more interesting topics in my EE classes on "high power"
systems. We toured a gas plant in Long Beach California which had 'internal
black start' capability. Sloshing all that power around is a complex business
and fraught with danger. Since I didn't expect to deal with much over 5V DC I
pretty much ignored the boring bits (only to have them come back to haunt me
when provisioning power in data centers.)

~~~
sillysaurus
_Sloshing all that power around is a complex business and fraught with
danger._

Why's that?

~~~
HCIdivision17
While not directly relevant, the scale and scope of such power transmission is
illustrated in an awesome anecdote by "Thomas L. Mc Mahon".

<http://www.jwz.org/blog/2002/11/engineering-pornography/>

Like JWZ, this has become a favorite of mine to share.

~~~
alphakappa
Ok, this is tangential, but how is it that one of the founders of
Netscape/Mozilla has a website that is so painful to look at? Flourescent
green on black.. my eyes!

~~~
sneak
You must be new here.

<http://www.secretgeometry.com/apps/cathode/>

~~~
gnu8
$10 for a gimmick program that will get used once?

~~~
sneak
$10 to tell the person who made it that we approve of the choices he's made in
his life.

I bought it because it simply existing brings me joy. It has the best you-
haven't-paid-yet nagware implementation ever conceived by man. I never even
triggered it (I bought it instantly) and it gives me joy that it exists.

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mrmagooey
Australia's energy regulator (<http://www.aemo.com.au/>) runs a separate
pricing market (ancillary) for producers who are able to provide black start
capability to the network, amongst other things like frequency regulation (I
think...).

~~~
mschaef
I can't speak for Australia, but I know that both are true for US pose
markets. Power is a big part of what's sold, but there are many other markets
too. Black start services, generation capacity, and frequency regulation, just
to name a few.

Part of the key to serving electrical demand is having a balanced mix of
generation to serve your load. Some units are better running flat out, some
are better for brief periods at peak demand, and some are good at quickly
taking up the slack if another unit fails. Different power markets exist
within the same geographical footprint to ensure that all these types of needs
(and more) are met. (24 hours a day, 7 days a week, and into the foreseeable
future.)

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mpyne
For fun, consider the question of how you'd "black start" from a loss of all
AC power on a submerged nuclear submarine? :)

~~~
ultimoo
I'm certain nuclear power submarines have two nuclear generators always
running to prevent this from happening. I also think they may have a diesel
powered generator for bootstrapping.

~~~
mpyne
Only 1 U.S. submarine has ever had 2 nuclear reactors (bonus points for those
who know why it was designed with 2).

Soviet submarines often had 2 though.

For the U.S. submarines they frequently would test shutting down the _1_
operational reactor at-sea and trying to recover from the casualty, just to
prove that it could be done when you didn't have time to pre-plan.

Edit: U.S. subs do have diesels though. So next question: how do you bring up
the diesel engine and its required auxiliaries without AC?

~~~
The_Fox
Here's the black start procedure for the 1950's-era ship I worked on. No idea
if this is at all similar to how they start diesels on a modern sub.

1\. Hand-crank a small diesel engine connected to a small air compressor.

2\. Use the small air compressor to build up pressure to start the emergency
diesel generator.

3\. Start the emergency diesel.

4\. Using the emergency power, run one of the large air compressors to build
up pressure for starting the main generators.

5\. Start the main generators.

The emergency diesel was near the stern of the ship, away from the generator
room, to ensure an generator room fire couldn't take out the emergency diesel.

~~~
mpyne
It's actually similar on a submarine, except that there's no need to hand-
crank an air compressor as we have tons of compressed air already available on
a submarine.

Also, once the diesel is running it is used to power the electrical buses that
provide the minimal pumps and other gear needed to recover the reactor and
eventually restart (or emergency restart) the turbogenerators that provide
ship's service power.

Unfortunately there's no room to have separate emergency generators and
emergency diesel so they are co-located.

~~~
Nrsolis
You skipped a step. LOLz.

~~~
mpyne
I skipped quite a few in fact. I love getting people interested in submarines
but I have no great desire to irritate my friends at NR by creeping past the
rules regarding NNPI (whether of the U variety or otherwise).

~~~
Nrsolis
I can appreciate that. And I was just having a little fun with you.

But I was simply referring to the part where you _surface the boat_ before
starting the diesels. I think some folks might be under the impression that
you can run those while submerged which is most decidedly NOT the case.

What I think many people don't realize is that a reactor shutdown is likely to
be a mission-over/career-ender type of deal for almost the entire officer
corps onboard. It's not supposed to happen EVER. It's like forgetting your gun
as you exit the helicopter.

BTW, It was "supposed to work" but didn't isn't an excuse. You (as an officer)
are responsible. That's what maintenance and drills are for. Reactor shuts
down and diesels won't come up? Wow. Major UNSAT. A dead-in-the-water carrier
is almost as bad as running the damn thing aground.

I'm wondering how the CNO felt about _that_ poodle-screw.

~~~
mpyne
You can run the diesels underwater though. Obviously there is a limit, but
surfacing the boat is neither required (sea state permitting) nor desired ("OH
LOOK, A SUB!!").

DIW on a CVN is a big deal, that is true (though hardly a career killer _by
itself_ for O-gang, even the ones in Reactor Department). NR takes nuclear
safety very seriously and the carrier won't sink just from loss of propulsion
so the reactors will very much be configured to fail conservative if
necessary.

Even on a submarine, which _can_ flounder without propulsion and only has a
single reactor, we do scram drills _all the time_. A scram can occur for no
better reason than that reactor protection was feeling finicky that day, so
the drills are designed to assume a scram _will_ happen, and recover safely
and efficiently.

On the other hand, an _unplanned_ scram really is one of those things which
may get someone disqualified from watchstanding, and possibly de-nuked
completely, since those usually represent a crew that doesn't properly respect
the power of the reactor.

~~~
Nrsolis
I don't know that I'd call running with the snorkel up anything but non-
submerged. Although I will give you that running at p-depth is almost the same
thing. I'm sure you'll agree that anything other than underway on main
propulsion is a far less preferable situation than normal ops.

BTW, I spent some time as a bubble-head, so I do understand what you're
talking about here. Just keep in mind that not everything you've heard about
subs is true and not everything I _knew_ about subs is still true. A lot has
changed since I was in.

------
iso8859-1
Here's a video of what used to be the world's largest diesel engine, used for
black starts if I remember correctly:

Built by Burmeister & Wain[1] , located at H.C. Ørstedværket [2]:
<https://www.youtube.com/watch?v=jPouLq3yZI8>

Maybe a diesel engine of this size was required since we don't have much hydro
power in Denmark (the article suggests starting a hydroelectric generating
station first).

[1]: <http://en.wikipedia.org/wiki/Burmeister_%26_Wain> [2]:
<http://en.wikipedia.org/wiki/H._C._%C3%98rsted_Power_Station>

~~~
jacquesm
And here is the current largest:

[http://en.wikipedia.org/wiki/W%C3%A4rtsil%C3%A4-Sulzer_RTA96...](http://en.wikipedia.org/wiki/W%C3%A4rtsil%C3%A4-Sulzer_RTA96-C)

------
sp332
I was wondering why nuclear plants require so much power to start up, when
really you can't "shut off" uranium's power-generation ability. I guess it
would have to do with powering up all the safety and management systems around
the generator?

~~~
aiiane
Uranium (or other radioactive materials) don't directly generate much
electricity - they mostly generate heat. Most nuclear power plants generate
electricity by having that heat turn water into steam, which is then used to
power steam turbines that actually drive the generator coils. Of course, in
order to do this, you have to be able to pump water into the reactor to be
turned into steam, and that pumping requires power. So yes, while you
definitely need power for the safety/management equipment, the major bootstrap
issue is almost certainly all of the power necessary for the pumps.

~~~
mseebach
The article touches on this:

 _Generating plants using steam turbines require station service power of up
to 10% of their capacity for boiler feedwater pumps, boiler forced-draft
combustion air blowers, and for fuel preparation._

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femto
Is Wikipedia's statement that hydro stations require an external source for
field excitation correct? I thought it was possible,to start a hydro generator
by "self-excitation". When a generator stops, there is typically a small
residual permanent magnetic field left, due to hysteresis. This small field
may be used to "bootstrap" the generator, whereby on initial spin up a small
current is generated, which may then be fed back to the field coil, further
exciting the generator's field and increasing the output, until full capacity
is reached.

All that is then required is a method of opening the penstock, which can
presumably be hand cranked?

~~~
mpyne
Permanent magnet excitation is a _possible_ way to generate the required field
flux for a generator, but it's not a _reliable_ way.

If the permanent magnetic field isn't strong enough you can't even generate
enough voltage to power-up the excitation circuit at all, and that's the
circuit which would feed the current back in.

So whether this is feasible or not depends on the generator design.

~~~
femto
I've got memories of some of the Snowy Mountains scheme's hydroelectric
generators being designed to start though self-excitation.

Wikipedia also has a bit about it [1]. It seems that there is usually a backup
facility to run a DC current though the field winding before starting, thus
magnetising the magnetic paths, for when the residual field has decayed too
much. That backs up your comments about reliability.

[1] <http://en.wikipedia.org/wiki/Self-excitation>

~~~
jacquesm
Residual flux is usually enough to start, but if you lose all flux for some
reason (when the core is completely demagnetize) zapping it with DC can help
restore it.

------
Mvandenbergh
Also important for black start capability are back-up batteries for the the
switching equipment. If those run out, then you won't be able to reconfigure
your network topology while bringing it up. Doing that manually takes a lot
longer and could add days to a black-out.

------
lmm
I think I remember reading that the phone system has nothing in place to do
the equivalent - all the equipment relies on getting its code from the rest of
the network, so if the entire phone network ever fell over there's no
procedure to start it again. Anyone know one way or the other?

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whtrbt
Noted for post-apocalypse.

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noxryan
This reminds me of how turbine aircraft usually start their engines. The
battery on these aircraft are used to start the APU (Auxiliary Power Unit)
which then starts the main engines. The APU is basically a generator, often in
the tail of the aircraft.

<https://en.wikipedia.org/wiki/Auxiliary_power_unit>

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justinph
Does this happen often? I suppose every time a plant gets shut down for
maintenance, but I don't see mention of catastrophic failures necessitating
many black starts.

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hayksaakian
Was there something in current events that prompted the rise of this post?

I didn't realize posting links to encyclopedia articles qualified as "hacker
news".

While I think the discussion is an interesting one, it's still odd to see a
random wikipedia article on the front page of HN

~~~
anthonyb
One of my projects at the moment is to make a hand cranked USB power source. I
stumbled across this while Googling for "stepper motor power generator" or
something like that. It looked interesting, so I submitted it.

~~~
hayksaakian
This makes the discussion much more interesting to me.

Thanks for the context.

