https://github.com/modelica/PowerSystems - pull requests are welcome and once accepted become part of the version shipped with OM.

I've checked the URL and it is was not that easy to me to understand how to pull requests.

Is going there the only way?

The modification I discussed is just a way to make Power Systems Library  more Modelica compliant.
Maybe if someone having access to that library maintenance has a look at this forum he can realize that in a few minutes he can significantly enlarge the number of Power Systems examples OM can run.
The suggesion came from the original author of the Power Systems Library.

Yes. It's the source of the library, so it's the logical place to make changes. We don't patch libraries except ModelicaServices and some old versions of MSL because it is better if it is fixed at the source so we don't need to patch the next release and the one after that. And the one where only whitespace changed and broke the patch, etc.

You either make a pull request (very simple; just do fork the repository, do git clone, git checkout -b nameOfMyTopicBranch, edit the files, git commit, git push, go to your repository, select the topic branch and choose to make a pull request). Or you can open an issue: https://github.com/modelica/PowerSystems/issues. But opening tickets without a pull request means someone needs to understand exactly what you want done, find the time to do it, and so on. With a pull request he just needs to verify that your changes are sane and then accept them.