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Dynamic simulation: oscillations without disturbance applied

asked 2021-08-27 09:49:26 -0500

cresg gravatar image

updated 2021-08-27 09:50:33 -0500

Hi everyone,

I am running dynamic simulation for a case study. Even before applying any disturbance, I see oscillations in plots for voltages, etc. which then settle at steady-state values after about 15 seconds.

The initial conditions check comes okay when the dynamic simulation is initialized. What, then, am I missing?

Any help will be highly appreciated.

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How big are the oscillations? What are the d-states?

likethevegetable gravatar imagelikethevegetable ( 2021-08-28 21:26:03 -0500 )edit

4 answers

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answered 2021-10-08 03:39:15 -0500

updated 2021-10-08 03:41:07 -0500

Check if you have small generator with classic gen model and no controller modelled(exciter,gov,pss ....). Draw the ouput of those units and check.

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The problem was solved on Oct 1...

perolofl gravatar imageperolofl ( 2021-10-08 04:05:05 -0500 )edit

answered 2021-10-01 02:15:33 -0500

cresg gravatar image

Update: The network had a user model for HVDC, and that's what was causing the issue. I replaced the model with a generic model and the oscillations went away. I am wondering what could be wrong with the user model since I don't have access to its source code.

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Is it a user model supplied with PSSE or is it a third-party model?

perolofl gravatar imageperolofl ( 2021-10-05 03:48:22 -0500 )edit

It's a third-party model.

cresg gravatar imagecresg ( 2021-10-05 03:57:21 -0500 )edit

answered 2021-09-27 19:55:29 -0500

bad_hand gravatar image

If you have SVCs and/or Statcoms in the case, plot their output. Their Q may be changing during initialization.

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answered 2021-08-30 03:25:16 -0500

perolofl gravatar image
  1. Check progress window for messages during the simulation.

  2. Use activity Compare (DIFF) to compare the load flow after 15 s simulation with the original saved case to see if there are any changes in bus voltages or line flow. This may indicate what is going on in the simulation.

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Asked: 2021-08-27 09:49:26 -0500

Seen: 368 times

Last updated: Oct 08 '21