Issue with IEEE-9 bus model and IEEE-39 bus (NW-39 segment) #5
Description
Hello,
I am currently working with the PSCAD benchmark models and have encountered a reproducible instability issue that appears to be related to exciter initialization.
Models tested
IEEE-9 bus system with synchronous generators and GFM inverters
IEEE-39 bus system (NW-39 segment only) with generators and GFMs
Observed behavior
In both models, the system remains stable until approximately 1 second, after which instability develops. During troubleshooting, I observed that the exciter status switches from 0 to 1 at ~1 s, indicating that the transition from fixed-voltage behavior to active excitation control may be triggering the issue.
Additional observations
A generator connected to a three-phase voltage source operates as expected and remains stable.
A generator operating alone also behaves normally.
When the generator is connected to a GFM inverter, the instability consistently appears after the exciter activates.
At this point, I am trying to determine whether this behavior is expected due to initialization settings or if there may be a configuration or parameter issue.
Any guidance on recommended initialization procedures, exciter settings, or parameters to verify would be greatly appreciated.
Thank you for making these models available.