Wrong result in a realistic, PowerGrids-based example

[ceraolo]

The attached OM.png and Dymola.png show variable IPu as obtained using the models ScTT and ScTT1 from the enclosed Test.mo. Note that this model requires PowerGrids library.

The two results should be identical since ScTT1 just adds some sensors to ScTT.
The Dymola's results are indeed identical.
The OM results are quite different, and the one from ScTT1 is badly wrong:

• the value during the first 100 ms is totally different (and invalid)
• the short circuit current (immediately after 100 ms) is too low
• the current, after an initial reduction after the short circuit occurring at 200ms, rises again: it should continuously reduce

Tested with OM v1.17.0-dev-141