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Constant current load model

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Hongda Ren
2018-08-31
2018-09-07
  • Hongda Ren

    Hongda Ren - 2018-08-31

    Hi OpenDSS engineer,

    I am courious about constant current load modeling in OpenDSS. Is that load current with constant current and current angle, which is contant when voltage and its angle change?
    Is it possible to connect constant current load by Delta connection? The circulating current may show within the connection.
    Could you give more details about constant current load model?

    Thanks,
    Hongda

     
  • Paulo Radatz

    Paulo Radatz - 2018-09-02

    Hello Hongda Ren,

    Current magnitude and power factor are constant for model 5. The current phaser is calculated by OpenDSS as follows:

    I = V/|V| x (Pn -jxQn)/|Vn|
    when Vminpu<V<Vmaxpu

    Where:
    V is the load voltage phaser
    Pn is the rated active power
    Qn is the reactive power
    Vn is the rated voltage.

    As you can see in this equation the current magnitude is constant, but the ent angle depends on the V angle.

    Yes, it is possible to use this model in loadsconnected in delta.

    You can find a good material with all equations used by OpenDSS inhe link below, the only problem is that the pdf is written in Portuguese, but I think you can handle it.

    https://drive.google.com/drive/u/2/folders/0B0GTsIi12nHXSl9ONG1pOWRhZW8?ogsrc=32

    Best Regards.

     
    • Hongda Ren

      Hongda Ren - 2018-09-07

      Hello Paulo,

      Thank you very much for detailed explanation. I try to simulate ZIP load model in OpenDSS with model 8 by seting ZIPV= [0,1,0,0,1,0,0.85]. Is that same model as model 5?
      Thank you again!
      Best,
      Hongda

       
  • Roger Dugan

    Roger Dugan - 2018-09-07

    I don't know if that ZIPV model will give the same answer as Model=5, but you can test it easily by using the BatchEdit command to generate the different load models and compare the results.

    Assuming the loads are initially defined as Model=8 and with ZIPV defined:

    ! Set all loads to model 5
    BatchEdit Load..* Model=5
    
    Solve
    
    ! inspect results
    ...
    
    ! Set back to Model 8
    BatchEdit Load..* Model=8
    
     

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