Simulink Power System Model Linearization using Linear Analysis Tool

Dear All,

I am using Matlab/Simulink 2016b to analyze power system stability. At the moment I am mainly interested in small signal stability which requires the system to be linearized around an operating point. For that I am using Simulink's Linear Analysis Tool.

My question is regarding the way linearization is carried out. I will try to ask the question by giving an example: - I have opened the Simulink model power_PSS which simulates the 2 area system described in the book Power System Stability and Control by Kundur. - I have linearized this model and verified the linear system response to the non-linear system response. They match quite well. - I have built my own Type 4 wind turbine model (that can run in phasor type simulations) and I have created a subsystem of my model. (this model is also linearizing correctly).

- next I have connected my model to the power_PSS model. The simulation is running and the results are as I expected. - Now, if I put my wind turbine model inside let's say Area 2 subsystem of the power_PSS model, the linearization is different than if I keep the wind turbine model outside the Area 2 subsystem. NOTE that in both cases I connect my model to the same BUS of the power_PSS model.

So my question is: Is there a rule on how/where the subsystems should be placed in a model in order to the linearization tool to properly linearize? I mention that in the second case, when the wind turbine model is outside of Area 2 the linear system response matches pretty well the non-linear response. In the first case they do not match.

Thank you all in advance for taking the time to read my question.

Best regards, Radu

[SinanB]

I would be also interested to hear the answer to this question!

[Awak Mathok]

Hello there, it might be a litle while ago but I need help in linearizing two area power system (power_PSS) same one yopu used for my research and am not able to generate all the state matrices. I am getting matrix A but B,C and D comes empty. I am using linmod to find my matrices. what do I need to do or which method can I use to get an answer?

Answer 1

[Zakaria Al-Soud]

Could help me please with the steps that you made to linearize the nonlinear wind turbine about a specific operating points

[Nyam Jargalsaikhan]

Dear Zakaria AI-Soud,

did you build the model how to linearize the wind turbine at specific operating points?

If you did this, could you please give some advice to me?

If you will help, I really appriciate to you.

Thank you very much