test: add IEEE 14-bus power-flow validation case

[VITA2aishu]

Adds an IEEE 14-bus symmetrical power-flow validation case for #984.

The case is based on the publicly available IEEE 14-bus test system and includes:

PGM input data for the 14-bus network
Newton-Raphson validation configuration
expected bus voltage magnitudes and angles
source and conversion documentation

The conversion includes PQ loads, PV generators with voltage regulation, the slack source, branch charging, transformer tap ratios, and the bus 9 shunt.

The reference solution was also independently checked using an AC Newton-Raphson calculation. The PGM repository validation/CI result is still to be confirmed, so I am opening this as a draft.

Related issue: #984

[Jerry-Jinfeng-Guo]

Hi @VITA2aishu , thank you for contributing this test case! Before we could proceed, could you add license file to each json as a standalone license file? You can take a look at the other test directories for reference. Once that is in place, we can approve the CI workflow.

[VITA2aishu]

Thanks! I’ve added the standalone license files for the three JSON files and pushed the changes. Please let me know if anything else is needed.

[figueroa1395]

Hello @VITA2aishu, we are a bit busy at the moment, so we expect to review the PR towards the end of the week or the beginning of the next week.

That said, I already see that some commits aren't properly DCO signed (see here) and that your commits also don't have the verified batch, which means that they aren't cryptographically signed either. You can find more information on the former here and on the latter here. Once you have amended the commits, you will have to force push. Let us know if we can be of any assistance.

In addition, if you want to make sure that everything was done correctly + all test pass + some code quality and formatting standards are satisfied, I recommend you do uv run pre-commit run locally, that way the process here can go more smoothly.

Finally, once your PR is ready to be reviewed, please mark it as ready (instead of draft) so that gives us the thumbs up.

Thanks again for the contribution.

[figueroa1395]

Hello @VITA2aishu,

I've reviewed and everything looks good (I just have a small comment). I also see that you have signed the previous commits as requested, thank you!

Hereby I've authorized CI to run. Let's see if anything needs to be adjusted then. I'll ping you once CI is through.

Note: I've also updated the base branch accordingly, so if changes are needed, make sure to adjust locally first.

Thanks for the contribution!

[nitbharambe]

The test cases look good!
Additionally versions of links:
caseformat/ieee14@a9e12bb
ITI/models@1d0d1e1

[Jerry-Jinfeng-Guo]

Hi @VITA2aishu , before we merge this new test case, can you let us know a bit more about how you calculated the results? I.e., can you disclose what is used in 'independently checked using an AC Newton-Raphson calculation'? Then we can proceed.

[nitbharambe]

The data matches from the links provided in the README.md.

Hi @VITA2aishu , before we merge this new test case, can you let us know a bit more about how you calculated the results? I.e., can you disclose what is used in 'independently checked using an AC Newton-Raphson calculation'? Then we can proceed.