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  • Users: NateKling
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  1. NateKling

    Reactance

    If Ksd = Ksq = 1/S100 Then as far as I understand, you can assume... Xdv = Ksd * (Xdi - Xl) + Xl and Xqv = Ksq * (Xqi - Xl) + Xl Can this be applied to the transient and sub-transient reactances as well? Thank you
  2. NateKling

    Saturated vs. Unsaturated

    Can anyone confirm: (Xdv - XL) = (1/S100)(Xdi-XL) and (Xqv - XL) = (1/S100)(Xqi-XL) As an estimate for saturated/unsaturated conversion. If so, would it be appropriate to apply this formula to transient and subtransient parameters as well?
  3. NateKling

    Saturated vs. Unsaturated

    Is there an equation to relate saturated and usaturated values for a synchronous generator. I have the S(1.0) and S(1.2) values with saturated T'do, T"do,T'qo,T"qo,Xd,Xq and unsaturated X'd,X'q,X"d=X"q, and Xl. Is there any way to calculate the missing fields? ....Saturated/Unsaturated...
  4. NateKling

    Inertia Constant - Generator

    The issue was in the power being rejected. it turns out the Auxiliary load and generator conditions were such that the rejected load was approximately 12.5 which just so happens to be 1/4 of 50. If it had been any other weird number, I probably would have figured that out right away but the...
  5. NateKling

    Inertia Constant - Generator

    ratz1: What was used to calculate/estimate H. J or WK2? The ratio between J and WK2 is 4. I think this may be where my problem is, but I am having trouble working it out mathematically. Would you mind explaining a little deeper?
  6. NateKling

    Inertia Constant - Generator

    @Marmite I was incorrect by concluding poles was the issue. By including the Initial and rate of change in the equation, the poles are accounted for. For example: dp * fo H = --------- 2 * df/dt To my understanding, the inertia constant is a perunitized resistance to change. The...
  7. NateKling

    Inertia Constant - Generator

    Disregard the last post, I forgot to replace 3600 with 1800 in excel. I am just about to give up on this. I can't figure out what I am doing wrong.
  8. NateKling

    Inertia Constant - Generator

    Ok, I now think that this definately has to do with the number of poles in the generator. When I simulated the LR Test with the exact same generator running at 1800 RPM with 4 Poles, and plugged the data into my spreadsheet, I was off by a factor of 8 instead of a factor of 4. So my equation...
  9. NateKling

    Inertia Constant - Generator

    The last excel sheet I uploaded depended on a different file. I was not aware of this. Sorry for the mistake. This file should work.http://files.engineering.com/getfile.aspx?folder=2390c73f-5da4-4048-8125-46ac70cb07b3&file=Load_Rejection_Inertia_Constant_Calculation.xlsx
  10. NateKling

    Inertia Constant - Generator

    Yes, that has all been considered in the model. The only error that I am running into is when I try to work backwards from the model data, back to my initial H constant. No matter what other factors come into play, I should be able to work back to the initial inertia constant because the data...
  11. NateKling

    Inertia Constant - Generator

    I am trying to simulate a test that would validate a generator's inertia. I just came up with some numbers for a large generator, and used standard parameters that I could find.
  12. NateKling

    Inertia Constant - Generator

    Here is some of the data from a test I simulated at four different hypothetical Inertia Constant values. Notice that the H_calc value is off by a factor of four each time. I still do not understand why this is happening. How would you suggest finding a J or WK2 value from a freq vs. time...
  13. NateKling

    Inertia Constant - Generator

    Well, that is something I was struggling to understand. I tried to work out and derive this formula using J and angular velocity and wr^2 and was unsuccessful with everything I tried. I was looking for some guidance with where I was going wrong. I think it is with that part of the formula though.
  14. NateKling

    Inertia Constant - Generator

    I am trying to calculate the Inertia constant of a generator for testing purposes using collected data. I also have software that will model transient stability studies. When I provide the model with the following information: H=2 MW = 50 MVA = 156.25 I recieve the following data, simulating...

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