Working with Frequency COI

[TimThacker]

Hantao, I have read through the documentation for ANDES and it appears that COI is built into ANDES, however I am unsure how to access it.

I am working on a frequency study in the WECC system, and I believe it would be easier to plot and work with the frequency COI. It seems that ss.COI.omega is empty, do I need to manually enter an index for each generator in the case file? Thank you.

[cuihantao]

Please take a look at kundur_coi.xlsx. In GENROU, you specify the idx of the linked COI to the coi field.

Then, in the COI sheet, you will create the COI instances with the proper idx and name, among others.

[TimThacker]

Hantao, I understand now that COI is implemented as if a new model is added to the system. How can I access the COI data? I am able to plot it by calling 'ss.TDS.plt.plot(ss.COI.omega)' but if I just call 'ss.COI.omega' I am not given something I can convert into a NumPy array. Could you explain the data structure to me?

Thank you!

[cuihantao]

These might be useful to you: https://docs.andes.app/en/latest/_examples/ex2.html#variables