Skip to main content

Error 171 | [PSS®E] | PSS®E crash


Relevant software:

PSS®E


Emitted message:

PSS®E suddenly (and unexpectedly) stopped running and/or responding to the gridmo Engine

Description:​

This error occurs when PSS®E suddenly (and unexpectedly) stopped running and/or responding to the gridmo Engine.

danger

The simulation will fail as PSS®E stopped running.

Possible impact:​

  • The simulation will terminate, but will automatically retry.

Potential fixes:​

Complete these steps first in the gridmo Engine, as they may resolve the issue:

  • If PSS®E Dynamic simulation, add the following in the Advanced Parameter field of the PSS®E Dynamic that had this error:
// attempts to make PSS®E more stable during numerical instability, not supported by all models.
legacy.invalid.number.support=yes  
// tells PSS®E to reattempt initialisation 5 times if it suspects the initialisation is unstable.
sim.repeat.init.if.suspect=5

Check the following files in the stand-alone folder for clues as to what is causing the instability:

  • server_log.log: This file has any exception information provided by PSS®E, which could indicate which user defined model (if any) is causing the issue.
  • psse_log.log: This file could include warning or error messages from built-in or user defined models which could provide a hint as to the error occurring.

Confirming the issue in PSS®E​

It is important to confirm this issue is also present in the stand-alone folder generated by the gridmo Engine.

  • Open the stand-alone folder of the PSS®E simulation that failed (if you do not see any zip files in the all-temp folder, ensure you have selected stand-alone folders to be generated in the Advanced drop-down on the simulation launch window).
  • Run the psse_macro.py provided by gridmo in the same PSS®E version as run by the gridmo Engine
  • If PSS®E crashes or the window disappears, the steps below may assist to identify the issue
  • If PSS®E does not crash and the macro completes - please reach out to gridmo support (as this might be a more complex issue which we can assist with).
danger

If you cannot reproduce the PSS®E crash directly in PSS®E, but it fails in the gridmo Engine - please reach out to gridmo support.

Note if the psse_macro.py file consistently crashes PSS®E, then you can continue to resolve the issue directly in PSS®E. Remember that any changes to the PSS®E source files (e.g. .sav or .dyr) need to be updated in your gridmo Engine's Inputs folder before you rerun to confirm the issue is resolved.

Crash on initialisation​

We've seen this error most commonly occur because of either:

  • A user defined model DLL having an unhandled error, or
  • A user defined model which is initialised outside of its crashed during dynamic initialization, or
  • A PSS®E internal model which has an extremely large STATE deviation on the first timestep (e.g. 'suspect initial conditions')

Cases we've seen include:

  • A custom model had terminal active power set to zero, below its minimum active power threshold. This was confirmed by an error log in the server_log.log file inside the stand-alone folder for the failing task.
    • The fix was to turn off the generator using SET, GEN=, STATUS=OUT rather than setting its terminal active power to 0.
  • A custom model being initialised with an unstable case file (which had a point of connection voltage of NaN).
    • The fix was to correct the static model instability (caused by conflicting voltage targets).
  • Models merged into a wide-area model but set out of service, where the custom model for the generator incorrectly initialises if the plant was out of service
    • The fix was to remove the custom DLL for that generator and/or remove its dyr record from the wide area dyr file.

Crash when running a command​

We've seen this error most commonly occur because of either:

  • The network being studied diverges substantially during or post fault, or
  • A user defined model enters into an unstable operating region.

This style of error can be hard to identify - if you have tried the above steps and the psse_macro.py macro consistently fails, please reach out to gridmo support.