Sloshing all that power around is a complex business and fraught with danger.
Why's that?
Why's that?
http://www.jwz.org/blog/2002/11/engineering-pornography/
Like JWZ, this has become a favorite of mine to share.
That, however, is taking nostalgia far beyond any sense of probity. It definitely ain't what it used to be.
https://github.com/Zygo/xscreensaver/blob/master/hacks/analo...
I have little doubt that all of jwz.org text rendering will be fully analogue-simulated once the monstrosity that is the supermajority of the installed base of web browsers supports such folly.
And yes, I'm familiar with the xanalogtv screensaver. Among my faves.
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.
That said, his recent "SOMA Nature Walk" series would appeal to people into big engineering.
The entire generator, including its concrete foundation, ripped itself out of the ground.
There was also the one about an electrician working on a generator who blasted himself with 66kV (low impedance). Massive burns, but he lived.
He used to work for a company called James Hardie, that made asbestos cement sheeting. Part of the process involved baking the sheets in a huge autoclave, like the one pictured here [1] (note the size of the man). An autoclave is an oven, filled with high pressure steam.
One day the door blew off the autoclave. The door disappeared, and the autoclave itself acted as a rocket, about the size of a shuttle solid fuel booster. It sheared off the bolts holding it to its foundation, rocketed though the back wall of the factory and ended up in a body of water about a mile away.
[1] http://museumvictoria.com.au/collections/items/756810/glass-...
I was in a gas-fired power plant when the call came in to spin up the plant turbine to meet demand. So as the turbine is spinning up, the guy misses the sync (which involves throwing a breaker when a certain light is almost extinguished; think incandescent) only to make it on the second try. At that point, the turbine goes into "follow" mode where the turbine speed is regulated to keep phase with the rest of the grid. Everything is going swimmingly until some surge causes a sudden increase in turbine speed followed by a sharp decrease. That's when the fun begins. The turbine can't spin down fast enough, which causes a phase differential, which causes a breaker to take a turbine big as a house to suddenly and violently be removed from the grid. This would normally cause an over-rev that would rip said turbine up from floor and into the air were it not for a bank of resistors that are outside that can produce a load for all that energy. When all that energy gets dumped into a bank of resistors in a switch yard on a hot summer day, you can smell it.
Electricity is no joke. Respect it.
The resultant current surge generated enough force and torque to physically lift the turbogenerator off of the deck before the breaker tripped. The amazing thing is that somehow the steam piping didn't rupture in the process.
Next year the aptly-named "sync check" modification was installed to prevent shutting the circuit breaker unless the two buses had approximately equal phase.
From what I can remember, the tolerance was about +/-5% and within that range, the generators would lock to each other. If one generator was putting out AC power that was ahead of the other, the current would cause the generator to behave like a motor and speed up until it matched. The other 350 degrees of the phase dial were much more dangerous ... explosions, physical damage, etc.
The actual EE-ish problem with black starts is that darn control systems class the EEs have to sit thru full of bode stability plots and stuff.
The problem is that power plants and the innards are kind of like highly tuned race car engines. The peak of technological performance at 1000 horsepower out, but at idle they get kinda squirrelly and don't really know what to do so as not to oscillate and/or stall and/or blow themselves up. For the signal/telecom EE types, black start is kind of like having a very high power finicky high gain amplifier with no decent termination and no real input and not much control, the odds of that dude deciding to oscillate are unfortunately high. Another way to put it is "the grid" is more or less predictable constant impedance you can smoothly and predictably match to, but connected to nothing during a black start or initial power up is very much like keying a high power radio transmitter when not connected to an antenna or dummy load, its going to be pretty impressive no matter if it blows up or not.
Theres some interesting impedance issues. An alternator is kinda like a constant current source, for a given field winding current it'll squirt out a much higher current from the main windings. And inductors don't like to change their current flow. And the only limit to the voltage is arc over and/or the internal resistance of the winding (well.. AC is much more complicated, but..) So overexcite the field winding on a connected gen and the voltage across town goes up a hundredth of a volt who cares. Overexcite a unconnected / black start gen and it could just arc over and explode or blow transformers and just F the place all up in general. Dump an extra megawatt-hour of energy in the general direction of Chicago and Chicago doesn't sniffle, dump it into one little piece of switchgear in the yard all by itself because its disconnected / blackstarting and the arc blows it to pieces.
Another issue not at his relatively boring gas turbine plant is stuff like differential thermal expansion. You have to heat and cool boilers and steam turbos slowly or else differential expansion can rip them apart. Supposedly if you leak even a little steam on a stationary turbine it'll expand one side enough while leaving the other side unexpanded and cold that when you slam the valve open its an open guess if you'll destroy the bearings from vibration or smash the blades into the outside of the turbine. So you keep them spinning, even if its really slow like 10 RPM, all the time, forever, unless you've got a crane on site to replace. And boilers blow up if you heat them too quickly, same problem with parts at different temps.
Gas turbos are tougher than steam turbos for a variety of reasons one being they're so dang hot and so much outside air (full of bugs and stuff) flows thru them that they can't build to the tolerances that a steam turbo can use, so they don't even try, so powering one up isn't as exciting as you'd think. Oh its loud, but not as exciting as spinning up a steamie.
Another fun feature is black starting is pretty hard on your whole backup system. Idling the diesel for 15 minutes a week is not quite as exciting as slamming it open full throttle for 12 hours while you heat up the main boiler or whatever. So if you're going to blow up your UPS / diesel / whatever its going to happen at black start time.
There's a general engineering rule that its a heck of a lot easier to design something that constantly does the same thing than something that varies, maybe randomly.