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Storing current values to Matlab and currents definition

Beginners
2015-10-08
2015-10-09
  • Victor Gutierrez

    Hi
    I have some questions regarding the results obtained from OpenDSS:

    1. Using the Export Current command in the COM interface two columns appear "Iresid1" and "AngResid1". What do this values represent? Reading the documentation I found that when OpenDSS calculates current elements check nodal voltages and the corresponding Y matrix to calculate the current but I haven´t find something related to these values.

    2. I´m using OpenDSS as a PF solver to develop a three-phase unbalanced OPF. The currents of the elements are obtained by the following code in Matlab:

      ElemNames=DSSCircuit.AllElementNames
      stringsNames = char(ElemNames)
      NumElements=DSSCircuit.NumCktElements
      for i=1:NumElements
      Name=strcat(stringsNames(i,:))
      DSSCircuit.SetActiveElement(Name)
      DSSActiveCktElement=DSSCircuit.ActiveCktElement
      Current = DSSActiveCktElement.Currents
      strcurrent={strcurrent,Current}
      end

      and I have two questions related to this:

      a) The values obtained with DSSActiveCktElement.Currents are different to those obtained with the Export Currents command, for instance for the IEEE 13-node system the currents of the line "Line.671692" are

      Using Matlab code: 216.9876 -78.8668 33.7996 -55.4262 -54.3425 168.4293 -216.9876 78.8668 -33.7996 55.4262 54.3425 -168.4293

    Using Export Command: 230.876 -19.97 64.919 -58.62 176.979 107.88 230.876 160.03 64.919 121.38 176.979 -72.12
    Why these values are so different?

    b) Does anybody has posted some sort of code to store results directly to a Matlab matrix?

    Thank you very much and I look forward to hearing back from you.
    Regards

     
  • Roger Dugan

    Roger Dugan - 2015-10-08

    Iresid1 is the magnitude of the "residual" current at terminal 1. That is, the sum of all conductors in terminal 1. It is sometimes the earth current. The next parameter is the angle of the residual current.

    a) the first is complex number (real, imaginary) pairs; the Export command gives (magnitude, angle) pairs.

    b) I think there is a posting showing that. Search for the 'reshape' function.

     
    • Victor Gutierrez

      Thank you very much for your prompt response.
      Regards.

       

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