Hi Debmalya,
The IEEE 33 Bus System model is available for various power system studies and can be accessed through the following link:-
This resource should provide you with a simple model for basic simulations, as well as a more comprehensive model suitable for in-depth control and analysis. You may need to set up the system's bus data, and any other relevant components in PSAT's required data files.
You can also find an IEEE 33 radial bus model that can be used in PSAT within the conference paper linked below. The paper includes simulations carried out on PSAT, and the test system is designed in Simulink using the PSAT library. I have highlighted the relevant system model discussed in the research paper, which can be accessed via the link provided below:-https://www.researchgate.net/publication/330540921_Comparative_Analysis_of_Radial_and_Looped_Distribution_Network_Against_Voltage_Stability_and_Loadability_with_Distributed_Generation#:~:text=Fig.%202.-,IEEE%2033%20radial%20bus%20system%20on%20PSAT,-III.%20S
I hope this helps
