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Strange machine angle behaviour in dynamics when breaking up run() calls

asked May 26 '0

boat14 gravatar image

I'm seeing deviations in flat runs in dynamics when I break up my psspy.run() commands.

The reason I'm concerned is this behaviour is not expected. My understanding is that I can break a simulation up into multiple segments, even if nothing happens between the two.

For example, if I do a flat 30 second run with just one psspy.run() command, all machine angles are flat and are consistent with each other:

psspy.run(  tpause  = 30,
            nprt    = 0,
            nplt    = 5,
            crtplt  = 0
            )

However, if I do a 30 second run, broken up into multiple parts, one of the machine's angles starts to deviate after the first psspy.run() command (for 1 second of initialization):

psspy.run(  tpause  = 1.0,
            nprt    = 0,
            nplt    = 5,
            crtplt  = 0
            )
# [Do contingency actions here]
psspy.run(  tpause  = 30,
            nprt    = 0,
            nplt    = 5,
            crtplt  = 0
            )

I have a list of contingencies that is used as an input for a dynamics simulation loop. The first "contingency" is a no fault run to compare the other contingencies against. So in the code above, the [Do contingency actions here] segment would be:

  • A non-operation for the "no fault" contingency.
  • A series of actions for other contingency tests.

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answered May 26 '0

perolofl gravatar image

A pause shall not affect the simulation results. Something is wrong in your model.

Check the dynamic models for the generators, especially for the generator with changing rotor angle.

If a user model is used, replace it with a library model.

link

Comments

Thanks - it is a custom model, which makes it a little harder to troubleshoot.

boat14 gravatar imageboat14 (May 26 '0)

What kind of generator is it? Synchronous or RE?

perolofl gravatar imageperolofl (May 26 '0)

After more investigation, it is RE (Renewable Energy?). Which explains why the angle is drifting. I should be disregarding that machine's angle since it's not tied to the system.

boat14 gravatar imageboat14 (May 26 '0)

Yes, for a RE generator rotor angle is meaningless. Check Eterm, Pelec and Qelec for the machine instead.

perolofl gravatar imageperolofl (May 26 '0)

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Asked: May 26 '0

Seen: 378 times

Last updated: May 26 '20