Nuclear Generator in model?

[pajce]

I wonder what would Nuclear generation plant generator be modeled with? I use software that gives some generic recommended values for impedances and time constants. I wonder if I can use this as a setting for my NUG? Is this going to be Steam Turbine Large?

 

[DanDel]

You may be confusing the generator with the prime mover. A nuclear plant provides steam for the prime mover which turns the generator.
The generator doesn't know where the heated steam comes from, all you need to know for the model is that the prime mover is basically a steam turbine.

From your post, I'm assuming your software has a default 'Steam Turbine Large' that includes the parameters for a generator being driven by a 'large' steam turbine. Typically, you can pick the generator size, and then the prime mover separately. What software are you using?

 

[byrdj]

The speed governors for BWR steam turbines are normally set at HSS. And load controlled by pressure governor.

Where a PWR is normally on the speed governor even if it is base loaded

 

[magoo2]

I agree what DanDel told you. In addition, you'll find large fossil powered steam generators are all 2-pole design. The nuclear stations use 4-pole generators. For the same MVA, a 4-pole generator would have a larger diameter and more inertia.

So my only suggestion is to see if the software has a 4-pole option to select.

 

[pajce]

I am using PSS Adept (Siemens)
Options are: (for Synchronous Machine Impedances)

Hydro with damper
hydro w/o damper
Steam Turbine Large
Steam Turbine Small
Combustible
Custom

Each option provides typical generator impedances and time constants. I understand this is prime mover but they link them to different gens designs. I wonder what is my option for nuclear gen ?

 

[pajce]

DenDel
I can put KVA rating , kV etc also in this model, but I am asking for impedances.

Thanks

 

[magoo2]

In Greenwood's book, you'll find the following ranges for transient and subtransient reactances:

2-pole turbine generators
x'd 0.12-0.21
x"d 0.07-0.14

4-pole turbine generators
x'd 0.20-0.28
x"d 0.12-0.17

I didn't find a value for xd but I think the range 1.2-1.3 is about right.

 

[DanDel]

pajce, the actual impedances and time constants are available from the generator manufacturer. Typically, the owner of the equipment has a submittal book for the unit with most if not all of the values you need.

Sounds like 'Steam Turbine Large' would fit the best out of those options for generic values