Fix PSSE parser of WTDTA1

[jinningwang]

• Fix equations of WTDTA1
• Fix WTDTA1 in PSSE parser
• Add non_negative=True to the param Mass in GENBASE, WTDTA1, WTDS

[jinningwang]

Hantao,

I compared the PowerWorld WTDTA1 and our implementation of WTDTA1, and I think that the equation of WTDTA1 in the PSSE parser should be modified.

Do I miss anything else?

Regards, Jinning

[codecov[bot]]

Codecov Report

Merging #279 (ac9de6a) into develop (d4ecf4c) will increase coverage by 0.00%. The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop     #279   +/-   ##
========================================
  Coverage    78.82%   78.82%           
========================================
  Files          152      152           
  Lines        12917    12918    +1     
========================================
+ Hits         10182    10183    +1     
  Misses        2735     2735           

Impacted Files	Coverage Δ
andes/models/renewable/wtds.py	100.00% <ø> (ø)
andes/models/synchronous/genbase.py	89.33% <ø> (ø)
andes/models/renewable/wtdta1.py	100.00% <100.00%> (ø)

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[cuihantao]

Thanks for the PR!

Can you modify the PSSE parser to allow the use of a variable, sys_f, in any equation? This seems to be a much needed feature.

[cuihantao]

I made a mistake in the original equation by forgetting about the square. Can you analyze the control diagram and figure out if Freq1 need to be converted to per unit? Recall that in WTDTA1 in ANDES, all other quantities such as H, D, omega are in per unit in system base. The unit of Freq1 should be consistent for the swing equations.

[jinningwang]

Thanks for the PR!

Can you modify the PSSE parser to allow the use of a variable, sys_f, in any equation? This seems to be a much needed feature.

Sure thing, let me try some solutions.

[jinningwang]

I made a mistake in the original equation by forgetting about the square. Can you analyze the control diagram and figure out if Freq1 need to be converted to per unit? Recall that in WTDTA1 in ANDES, all other quantities such as H, D, omega are in per unit in system base. The unit of Freq1 should be consistent for the swing equations.

I'll check this.

[jinningwang]

Hantao, although PSSE doc said it is nominal frequency, I think per unit is more reasonable. In the test dyr file, the variable is given in per unit.

Regards, Jinning

[cuihantao]

Hantao, although PSSE doc said it is nominal frequency, I think per unit is more reasonable. In the test dyr file, the variable is given in per unit.

Something might be wrong here. Either the doc or PSS/E's not following the doc.

Anyway, what I asked you to do is to perform a rigorous analysis of the swing equation to reason if Freq1 needs to be in per unit or Hz. The manual is a reference, but an analysis is needed.

[jinningwang]

Hantao, although PSSE doc said it is nominal frequency, I think per unit is more reasonable. In the test dyr file, the variable is given in per unit.

Something might be wrong here. Either the doc or PSS/E's not following the doc.

Anyway, what I asked you to do is to perform a rigorous analysis of the swing equation to reason if Freq1 needs to be in per unit or Hz. The manual is a reference, but an analysis is needed.

Sure, let me do this after fixing the initialization error of WTDTA1.

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[jinningwang]

Wait, I noticed a bug, give me a moment.

Hantao,

I think this PR is ready to merge, all the issues related to WTDTA1 are solved:

• The Freq1 should be in per unit after I analyze the equations, I add notices in the docstring of WTDTA1;
• The initialization error is fixed when Kshaft=0.

The enhancement of adding sys_f in the PSSE parser can be done in another PR.

Regards, Jinning