There is a limit on the number of electrical nodes and components you can use in a single project.
To understand why finding a "free version" is difficult, one must understand the software's architecture. PSCAD is proprietary software protected by a sophisticated licensing system.
Cracked versions of simulation software are notorious for instability.
There have been documented cases of malware disguised as engineering tools. If you are working on a computer connected to a secure network (like a power utility or research lab), downloading a cracked version of PSCAD can introduce a backdoor into that network. This is not just a personal risk; it is a national security risk.
Studying sudden changes in power systems, such as lightning strikes or faults.