Three Phase dynamic load

Question

andre albagli 2015-3-23

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评论： jun 2024-6-26

Guys:

I´m an electric engineering student and I´m trying to create a IEEE-33 distribuion line topology with simulink as shown in figure 1. Source voltage is 138Kv and transformer reduces to 13.8 Kv.

 Instead of using fixed loads, I´m using three phase dynamic load with external control as show in figure 2.

 I´m facing a problem with with a very small model with three loads. Voltages and currents that are associated to these load models as show in figure 3 have strange behaviours. Results are like numeric noise. I was suspecting that the problem could be related with solve model but I tried fixed step and variable step with the same results.

Can anyone explain to me what is going on with the model and how to fix it ?

Sincerely, Andre Nudel

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Atieh Delavari 2015-8-26

编辑：Atieh Delavari 2015-8-26

Hi I think you should adjust configuration parameters to see better waves forms

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Answer 1

Sebastian Castro 2015-3-24

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It could very well be numerical noise. I noticed you are still using the ode45 solver, which is the default for Simulink.

If you open up Model Configuration Parameters, and go to the Solver pane, try:

Change the solver to "ode23tb"
Change the Relative Tolerance parameter from "auto" to "1e-4"

Both of these constitute the recommended settings for SimPowerSystems models, as shown in the power_new function.

If you still get noise, try further reducing the Relative Tolerance and Absolute Tolerance parameters, as well as the Max step size. This may help further.

- Sebastian

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andre albagli 2015-3-24

Sebastian :

Thanks for your answer. I´ll do it straightaway and let you know.

Thanks! Andre

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Answer 2

andre albagli 2015-3-24

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https://ww2.mathworks.cn/matlabcentral/answers/184675-three-phase-dynamic-load#answer_172617

Sebastian:

I tried to change these parameters but the results are the same. Any other sugestion ?

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jun 2024-6-26

Hello, I recently encountered a similar issue and found that the aforementioned method did not solve the problem. I added a three-phase circuit breaker in front of the Three-Phase Dynamic Load. After opening the circuit breaker, there was still significant voltage fluctuation at the front end of the breaker. I set the line voltage to 400V, but the actual voltage exceeded 100,000V. I found that the issue does not occur when no active and reactive power parameters are input for the load.

jun 2024-6-26