[bug] run_contingency_ls2g doesn't work when there are redundant buses

[awarsewa]

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• 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.networks as pn
import pandapower.contingency as pc
import pandapower as pp 

net = pn.case30()
# Create a redundant bus
pp.create_bus(net, vn_kv=135, name="31", index=30, zone="3.0", max_vm_pu =1.05, min_vm_pu=0.95) # create a new bus
pp.create_switch(net, bus=30, element=29, et="b", type="CB", closed=True) # create a new switch

# Try running contingency analysis
nminus1_cases = {
    "line": {"index": net.line.index.values},
    "gen": {"index": net.gen.index.values}
}
# Running contingency analysis here should fail
pc.run_contingency_ls2g(net, nminus1_cases)

Issue Description and Traceback

When there is a redundant bus, the size of Vinit is not equal to the number of buses anymore.
I had originally reported this in issue#2361 and finally wrote an example that reproduces this behaviour.

Traceback (most recent call last):
File "c:\Users\XXX\Python\pandapower\test_pp_ls2g.py", line 14, in
pc.run_contingency_ls2g(net, nminus1_cases)
File "C:\Users\XXX\anaconda3\envs\pandapower\Lib\site-packages\pandapower\contingency\contingency.py", line 225, in run_contingency_ls2g
s.compute(v_init, net._options["max_iteration"], net._options["tolerance_mva"])
RuntimeError: SecurityAnalysis::compute: Size of the Vinit should be the same as the total number of buses. Currently: Vinit: 30 and there are 31 buses.(fyi: Components of Vinit corresponding to deactivated bus will be ignored anyway, so you can put whatever you want there).

Expected Behavior

run_contingency_ls2g should be able to handle redundant buses e. g. by:

v_init = net._ppc["internal"]["V"][net._pd2ppc_lookups["bus"]]

Installed Versions

INSTALLED VERSIONS

commit : 0691c5cf90477d3503834d983f69350f250a6ff7
python : 3.12.7
python-bits : 64
OS : Windows
OS-release : 11
Version : 10.0.22631
machine : AMD64
processor : Intel64 Family 6 Model 140 Stepping 1, GenuineIntel
byteorder : little
LC_ALL : None
LANG : en_US.UTF-8
LOCALE : English_Australia.1252

pandas : 2.2.3
numpy : 1.26.4
pytz : 2024.2
dateutil : 2.9.0.post0
pip : 24.3.1
Cython : None
sphinx : None
IPython : None
adbc-driver-postgresql: None
adbc-driver-sqlite : None
bs4 : None
blosc : None
bottleneck : None
dataframe-api-compat : None
fastparquet : None
fsspec : None
html5lib : None
hypothesis : None
gcsfs : None
jinja2 : None
lxml.etree : None
matplotlib : None
numba : None
numexpr : None
odfpy : None
openpyxl : None
pandas_gbq : None
psycopg2 : None
pymysql : None
pyarrow : None
pyreadstat : None
pytest : None
python-calamine : None
pyxlsb : None
s3fs : None
scipy : 1.13.1
sqlalchemy : None
tables : None
tabulate : None
xarray : None
xlrd : None
xlsxwriter : None
zstandard : None
tzdata : 2024.2
qtpy : None
pyqt5 : None

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[vogt31337]

@awarsewa, id I understand you correctly this issue can be solved by using your reply: #2361 (comment) ?