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Convergence for power flow analysis shows inconsistent properties
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Issue
Hey,
I am currently running power flow analysis in order to generate the admittance matrix Ybus:
# Convert MATPOWER case to pandapower network
# mat_file_path is file to tree files
net = pc.from_mpc(
mat_file_path, f_hz=50, casename_mpc_file="mpc", validate_conversion=False
)
# Run power flow to calculate the Ybus matrix
pp.runpp(net)
Ybus = net._ppc["internal"]["Ybus"]
# Extract the conductance (G) and susceptance (B) matrices
G = Ybus.real
B = Ybus.imag
Now I am facing the issue, when I run those lines for the "case14Tree.m" that I receive the following error message:
/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/create.py:5049: FutureWarning: The behavior of DataFrame concatenation with empty or all-NA entries is deprecated. In a future version, this will no longer exclude empty or all-NA columns when determining the result dtypes. To retain the old behavior, exclude the relevant entries before the concat operation.
net[table] = pd.concat([net[table], dd[dd.columns[~dd.isnull().all()]]], sort=False)
/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/converter/pypower/from_ppc.py:199: RuntimeWarning: divide by zero encountered in divide
max_i_ka = ppc['branch'][:, 5]/ppc['bus'][to_bus, BASE_KV]/np.sqrt(3)
/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/converter/pypower/from_ppc.py:210: RuntimeWarning: divide by zero encountered in divide
c_nf_per_km=(ppc['branch'][is_line, BR_B]/Zni[is_line]/omega*1e9/2).real,
/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/converter/pypower/from_ppc.py:210: RuntimeWarning: invalid value encountered in divide
c_nf_per_km=(ppc['branch'][is_line, BR_B]/Zni[is_line]/omega*1e9/2).real,
/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/converter/pypower/from_ppc.py:277: FutureWarning: Setting an item of incompatible dtype is deprecated and will raise an error in a future version of pandas. Value '[]' has dtype incompatible with int64, please explicitly cast to a compatible dtype first.
branch_lookup.loc[~is_line, "element"] = idx_trafo
numba cannot be imported and numba functions are disabled.
Probably the execution is slow.
Please install numba to gain a massive speedup.
(or if you prefer slow execution, set the flag numba=False to avoid this warning!)
/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/build_branch.py:164: RuntimeWarning: invalid value encountered in divide
branch[f:t, BR_R] = line["r_ohm_per_km"].values * length_km / baseR / parallel
/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/build_branch.py:165: RuntimeWarning: invalid value encountered in divide
branch[f:t, BR_X] = line["x_ohm_per_km"].values * length_km / baseR / parallel
/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/build_branch.py:194: RuntimeWarning: invalid value encountered in multiply
b = 2 * net.f_hz * math.pi * line["c_nf_per_km"].values * 1e-9 * baseR * length_km * parallel
/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/build_branch.py:206: RuntimeWarning: invalid value encountered in multiply
branch[f:t, RATE_A] = max_load / 100. * max_i_ka * df * parallel * vr
/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/build_bus.py:487: RuntimeWarning: invalid value encountered in divide
v_ratio = (ppc["bus"][bus_lookup[s["bus"].values], BASE_KV] / s["vn_kv"].values) ** 2 * base_multiplier
/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/pypower/makeBdc.py:97: RuntimeWarning: invalid value encountered in divide
b = stat / branch[:, BR_X] ## series susceptance
/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/scipy/sparse/linalg/_dsolve/linsolve.py:293: MatrixRankWarning: Matrix is exactly singular
warn("Matrix is exactly singular", MatrixRankWarning)
/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/pypower/makeYbus.py:82: RuntimeWarning: invalid value encountered in divide
Ysf = stat / (branch[:, BR_R] + 1j * branch[:, BR_X]) ## series admittance
/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/pypower/dSbus_dV.py:34: RuntimeWarning: invalid value encountered in divide
diagVnorm = sparse((V / abs(V), (ib, ib)))
Traceback (most recent call last):
File "/Users/PaulKandora/PyCharm_projects/CopOpf/copopf/test_soc_on_large_instances.py", line 124, in <module>
opf_data = extract_opf_data('Tree_Library/case14Tree.m')
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/PaulKandora/PyCharm_projects/CopOpf/copopf/extract_opf_data_from_matlab.py", line 13, in extract_opf_data
pp.runpp(net)
File "/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/run.py", line 250, in runpp
_powerflow(net, **kwargs)
File "/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/powerflow.py", line 86, in _powerflow
_ppci_to_net(result, net)
File "/Users/PaulKandora/opt/anaconda3/envs/copopf/lib/python3.12/site-packages/pandapower/powerflow.py", line 190, in _ppci_to_net
raise LoadflowNotConverged("Power Flow {0} did not converge after "
pandapower.powerflow.LoadflowNotConverged: Power Flow nr did not converge after 10 iterations!
I assumed that the issue was related to dimensionality of the dataset but when I run the code on higher dimensional cases such as "case30Tree.m", I receive the correct results. Probably, it is not the best approach to generate admittance matrix (grateful if you know a better way to do so) but not sure how to resolve this issue.
Thanks in advance and best regards,
Paul
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Dear @Paulnkk,
I agree that numerical issues might arise when trying to solve the power flow with the converted grid data. You can try to run pp.diagnostic(net) after receiving the data from matpower conversion. Maybe some r, x, or b values are extreme, for some reason.
@SteffenMeinecke thanks a lot for the suggestion, I will try the approach you proposed and try to fix the issue
@Paulnkk still relevant? I have seen in another issue, that pp does something with zero impedance lines, which seem to be part of the case14 maybe this is a hint why your results are weird.
@vogt31337 thanks for the response! Yes this case is still relevant for me, I planned to check in detail tomorrow
@vogt31337 I checked and the issue mainly comes from the fact that baseKV in my ieee 14 bus case is 0. I am considering radial networks from here: https://www.dropbox.com/scl/fi/ohc1xd4g03u1ch0356zgj/Tree-Library.zip?rlkey=crey52c766o03chsxgjytsrfa&e=1&dl=0
I will try to use the baseKV from the standard MATPOWER case file for the IEEE 14-bus system and check if results are correcr