From 9f00fa701b76c1d59ba0bd3b0fbef620b4674528 Mon Sep 17 00:00:00 2001
From: joda9 <jonas.danke@rl-institut.de>
Date: Mon, 22 Jul 2024 14:26:17 +0200
Subject: [PATCH] Add warning if meshes are in the grid

---
 edisgo/opf/powermodels_opf.py     | 28 ++++++++++++++++++++++++++++
 tests/opf/test_powermodels_opf.py | 27 ++++++++++++++++++++++++++-
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/edisgo/opf/powermodels_opf.py b/edisgo/opf/powermodels_opf.py
index db4925d3b..2d082f0cf 100644
--- a/edisgo/opf/powermodels_opf.py
+++ b/edisgo/opf/powermodels_opf.py
@@ -4,6 +4,7 @@
 import subprocess
 import sys
 
+import networkx as nx
 import numpy as np
 
 from edisgo.flex_opt import exceptions
@@ -12,6 +13,32 @@
 logger = logging.getLogger(__name__)
 
 
+def find_meshes(edisgo_obj) -> list:
+    """
+    Find all meshes in the grid.
+
+    Parameters
+    ----------
+    edisgo_obj : :class:`~edisgo.EDisGo`
+        EDisGo object.
+
+    Returns
+    -------
+    meshes : list
+        List of all meshes in the grid.
+
+    """
+    meshes = nx.cycle_basis(edisgo_obj.to_graph())
+    if meshes:
+        logger.warning(
+            "Grid contains mesh(es). This might cause problems in "
+            "the power flow or optimisation."
+        )
+        return meshes
+    else:
+        return None
+
+
 def pm_optimize(
     edisgo_obj,
     s_base=1,
@@ -105,6 +132,7 @@ def pm_optimize(
         Default: True.
 
     """
+    find_meshes(edisgo_obj)
     opf_dir = os.path.dirname(os.path.abspath(__file__))
     solution_dir = os.path.join(opf_dir, "opf_solutions")
     pm, hv_flex_dict = edisgo_obj.to_powermodels(
diff --git a/tests/opf/test_powermodels_opf.py b/tests/opf/test_powermodels_opf.py
index 4f6482f97..931a7cb6b 100644
--- a/tests/opf/test_powermodels_opf.py
+++ b/tests/opf/test_powermodels_opf.py
@@ -3,7 +3,7 @@
 import pytest
 
 from edisgo import EDisGo
-from edisgo.opf.powermodels_opf import pm_optimize
+from edisgo.opf.powermodels_opf import find_meshes, pm_optimize
 from edisgo.tools.tools import aggregate_district_heating_components
 
 
@@ -337,3 +337,28 @@ def test_pm_optimize(self):
                 )
             )
         )
+
+    def test_find_meshes(self, caplog):
+        meshes = find_meshes(self.edisgo)
+        assert not meshes
+        self.edisgo.topology.add_line(
+            "Bus_GeneratorFluctuating_2",
+            "Bus_GeneratorFluctuating_6",
+            0.1,
+            x=0.1,
+            r=0.1,
+        )
+        meshes = find_meshes(self.edisgo)
+        assert len(meshes) == 1
+        assert "Bus_GeneratorFluctuating_2" in meshes[0]
+        assert "Bus_GeneratorFluctuating_6" in meshes[0]
+        self.edisgo.topology.add_line(
+            "Bus_BranchTee_LVGrid_2_3", "Bus_BranchTee_LVGrid_3_3", 0.1, x=0.1, r=0.1
+        )
+        meshes = find_meshes(self.edisgo)
+        assert len(meshes) == 2
+        assert "Bus_BranchTee_LVGrid_2_3" in meshes[1]
+        assert (
+            "Grid contains mesh(es). This might cause problems"
+            " in the power flow or optimisation." in caplog.text
+        )