[Load flow] Add warning when connecting voltage levels with different nominal voltages

[FredericSabot]

• Do you want to request a feature or report a bug?

Feature

• What is the current behavior?

Currently, it is possible to accidentally connect, say a 400kV bus to a 220kV one which can lead to weird load flow results (in my case, I also obtain different results when using itools and pypowsybl, maybe because of different versions/default parameters).

• What is the expected behavior?

Output a warning when computing a load flow for such invalid cases (I guess no warning should be given for connections between 380 and 400KV buses).

• Please tell us about your environment:
  • PowSyBl Version: ...
  • OS Version: Ubuntu 22.04

[geofjamg]

Do you have a small example with such a configuration and given / expected results?

[FredericSabot]

Upon further examination and installation of a more recent itools distribution, both tools give the expected results (results are actually independent of the nominal_v of buses, and only depend on the generator/transformer ratings. This was not the case with v1.4 of powsybl.

My point was mainly that a warning could be output when a line is used to connect voltage levels with significantly different nominal_v as this is most likely an error from the user.

eurostag_itools_old.txt eurostag_pypowsybl.txt