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The more interesting thing about rotating power plants is that they are routinely destroyed by transmission outages, because when a rotating generator is sudden
by jeffbee 2y ago
The more interesting thing about rotating power plants is that they are routinely destroyed by transmission outages, because when a rotating generator is suddenly disconnected from its load, there are infinity terms in the equations that govern its motion and infinity isn't a thing you can resist. For steam turbines the control system has to slam the valve shut on the steam, otherwise the machine would overspeed, and closing that valve destroys some sacrificial part of the steam plumbing (hopefully). Steam power plants have to be inspected and repaired after disconnects and this is one of the numerous reasons why fission kinda sucks on the reliability front.
- m463 2y agoI don't see why there can't be load resistors (like locomotives use) to gracefully handle these sorts of situations.
- Qwertious 2y agoWell if you can solve it, I imagine there's a lot of money to be made - and yet it hasn't been solved.
- jeffbee 2y agoAn SD40 locomotive can dissipate about 500kW that way, so you would need the equivalent of 2000 locomotives worth of resistors and fans to sink the 1 or 2GW or more that a fission power station produces.
- rcxdude 2y agoIf you wanted to do so continuously. If you're just handling an impulse you don't need so much, but it's gotta absorb a lot of energy quickly.
- rcxdude 2y agoWhile the infinity terms may be a useful way to think about how the system loses stability, I think it's better to think of it in terms of energy: at any given time there's some amount of energy that's been injected into the system in the form of hot gas which hasn't been converted yet. Even a few seconds worth is a lot of energy, and if the electrical load is removed, that energy has to go somewhere.
- 31carmichael 2y agoThis is true only if the protection does not operate as designed. They are NOT routinely destroyed by transmission outages. You have been misinformed. Rotating machines cannot overspeed instantly, as they have inertia.
- jeffbee 2y agoDozens of power plants blew up steam rupture disks during the 2003 northeast outage. EPA, FERC, and NYISO all mention this in their reports.