Ask me about industrial electricity 2: electric boogaloo

The Something Awful Forums > Discussion > Ask/Tell > Ask me about industrial electricity 2: electric boogaloo

Gisnep: Mar 29, 2010

Ossetepo posted:

Plants that have motor-driven auxiliary feedwater pumps also have two sets per unit of 24VDC batteries for starting those

How does that work? Do they start and run on DC power until the diesels have time to tie on?

My plant is a Westinghouse four-loop as well, but our motor-driven aux feedwater pumps only use batteries for 125VDC control power.

# ¿ Oct 1, 2011 16:08

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Gisnep: Mar 29, 2010

Three-Phase posted:

Now I can see where the generator is, but what's the deal with that little "building" at the end? I know sometimes you can mount a brushless exciter or connections for an external exciter (slip-rings connected to the rotor) on the far end

You're right, that little building does house the exciter.

It's a similar setup to what you see on this page: http://www.mhi.co.jp/en/products/detail/turbine_generator_system.html

# ¿ Apr 19, 2013 22:33

Gisnep: Mar 29, 2010

Exploding Barrel posted:

I've never seen a power plant that small or set up like that so I was hoping someone in this thread had any info on an installation like this.

That's a combustion turbine plant.

http://www.tva.com/power/cumb_turbineart.htm

They are usually used for supplying electricity during periods of peak demand. They are expensive to run, but can be started or shutdown quickly to accommodate changes in grid loading.

# ¿ Aug 19, 2013 02:20

Gisnep: Mar 29, 2010

thylacine posted:

https://www.google.com/maps/preview...i955!4f35&fid=7

I saw the "what is this" chat earlier. I'm curios as to what type of plant this is.

That's the Gordon Evans Energy Center. I think it's a natural gas boiler power plant, and there looks to be some combustion turbines at the south end as well.

# ¿ Sep 29, 2013 03:10

Gisnep: Mar 29, 2010

I found an interesting video of a nuclear power plant simulator training scenario. This is a large-break loss of coolant accident at a PWR, with a reactor trip and safety injection.

https://www.youtube.com/watch?v=swr74_CDyLk

# ¿ Jan 17, 2014 00:05

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# ¿ May 3, 2024 14:55

Gisnep: Mar 29, 2010

Three-Phase posted:

One of the questions I'd like to figure out is how to gracefully "un-parallel" a generator. If you have a power plant with, say, three 100MW generators, and you need to take one offline without impacting the power grid, how would that be accomplished?

I think the way to do that with a synchronous generator connected to a turbine would be to slowly throttle back the turbine until you get to a point where there is zero current flowing out of the generator or you actually go into the opposite quadrant and begin to run the generator as a motor, and then you can cut excitation and open the circuit breaker.

Our preferred method is by gradually lowering turbine loading to ~20% over 6-7 hours, then we close the turbine inlet valves completely. The generator remains connected to the grid and motors the turbine for about 30 seconds until the reverse power relay (or possibly another relay) times out and opens the generator output breaker. This is with 1200MW generators.

We don't always reduce power that slowly though, it's just preferred for the sake of the rest of our plant equipment rather than concern for the grid. We might have a situation that warrants a 4% per minute load reduction. We also have automatic load reductions that will shed 320MW in about 9 seconds. Or we might just trip offline from 100% power due to some fault.

quote:

The problem with just opening the circuit breaker (assuming you have a generator breaker and aren't utilizing a higher-voltage breaker upstream) would be:
Creating a disturbance in the power system - if that generator was running at 75MW the grid would need to respond quickly

I'm not sure how much of a disturbance we create even when tripping a 1200MW generator. I know there are things in place to lessen the impact.

quote:

The turbine would need to respond quickly to avoid an overspeed (you've lost what was absorbing power from the turbine, effectively you've lost the brake)

We have a circuit that continuously monitors generator electrical output and compares it to the turbine steam inlet pressure. If it senses a significant mismatch between the two, it will automatically throttle the turbine inlet valves to prevent an overspeed.

quote:

You'd have to kill excitation quickly to ensure you don't excite an open-circuit stator and damage it from generating a very high voltage

We have over-excitation protective relays that will trip the exciter breaker. The relays have a more conservative setting when the generator output breaker is open.

Gisnep fucked around with this message at 15:44 on Feb 4, 2014

# ¿ Feb 4, 2014 15:37

The Something Awful Forums > Discussion > Ask/Tell > Ask me about industrial electricity 2: electric boogaloo