Unexpected output from to_mpc()

[lefang16]

Bug report checklis

• Searched the issues page for similar reports

• Read the relevant sections of the documentation

• Browse the tutorials and tests for usefull code snippets and examples of use

• Reproduced the issue after updating with pip install --upgrade pandapower (or git pull)

• Tried basic troubleshooting (if a bug/error) like restarting the interpreter and checking the pythonpath

Reproducible Example

import pandapower as pp
import pandapower.networks as pn
net=pn.case118()
pp.runpp(net)  # added 
pp.converter.to_mpc(net=net, filename="case118.mat")

Issue Description and Traceback

The produced .mat matrix contains more columns (zeros) than the standard mpc format case for bus, etc., the bus should have 13 columns for the version 2 matpower case.

Expected Behavior

should output a standard matpower case

Installed Versions

python : 3.9.20.final.0
python-bits : 64
OS : Darwin
OS-release : 24.1.0
pandas : 2.2.2
numpy : 1.26.4
pytz : 2024.1
dateutil : 2.9.0.post0
setuptools : 75.1.0
pip : 24.2
Cython : None
pytest : 8.3.3
IPython : 8.18.1
bottleneck : 1.3.7
matplotlib : 3.9.2
numba : 0.60.0
numexpr : 2.8.7
scipy : 1.13.1

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[vogt31337]

@lefang16, it seems like the version tag is not set correctly, since in https://www.matpower.org/docs/manual.pdf page 141 there are 16 columns stated for the bus table.
If you look into pandapower/pypower/idx_bus.py and open the old 2.0 manual, you can compare the column Ids and see, that only the first 12 are needed and are exactly the same. So quick fix would be to just "crop" your matrix.