Fix: update confusing private name

src/power_grid_model_ds/_core/model/grids/base.py

@@ -221,7 +221,7 @@ def delete_branch(self, branch: BranchArray) -> None:
         Args:
             branch (BranchArray): The branch to remove
         """
-        _add_branch_array(branch=branch, grid=self)
+        _delete_branch_array(branch=branch, grid=self)
         self.graphs.delete_branch(branch=branch)
         logging.debug(
             f"""deleted branch {branch.id.item()} from {branch.from_node.item()} to {branch.to_node.item()}"""
@@ -233,7 +233,7 @@ def delete_branch3(self, branch: Branch3Array) -> None:
         Args:
             branch (Branch3Array): The branch3 to remove
         """
-        _add_branch_array(branch=branch, grid=self)
+        _delete_branch_array(branch=branch, grid=self)
         self.graphs.delete_branch3(branch=branch)
 
     def add_node(self, node: NodeArray) -> None:
@@ -459,8 +459,8 @@ def from_extended(cls, extended: "Grid") -> "Grid":
         return new_grid
 
 
-def _add_branch_array(branch: BranchArray | Branch3Array, grid: Grid):
-    """Add a branch array to the grid"""
+def _delete_branch_array(branch: BranchArray | Branch3Array, grid: Grid):
+    """Delete a branch array from the grid"""
     array_field = grid.find_array_field(branch.__class__)
     array_attr = getattr(grid, array_field.name)
     setattr(grid, array_field.name, array_attr.exclude(id=branch.id))

tests/unit/model/grids/test_grid_base.py

@@ -15,6 +15,7 @@
     LineArray,
     LinkArray,
     NodeArray,
+    ThreeWindingTransformerArray,
     TransformerArray,
     TransformerTapRegulatorArray,
 )
@@ -227,6 +228,42 @@ def test_grid_delete_tranformer(basic_grid: Grid):
     assert not grid.graphs.complete_graph.has_branch(transformer.from_node.item(), transformer.to_node.item())
 
 
+def test_grid_add_three_winding_transformer():
+    grid = Grid.empty()
+    nodes = NodeArray.zeros(3)
+    nodes.id = [102, 103, 104]
+    grid.append(nodes)
+
+    three_winding_transformer = ThreeWindingTransformerArray.zeros(1)
+    three_winding_transformer.node_1 = 102
+    three_winding_transformer.node_2 = 103
+    three_winding_transformer.node_3 = 104
+    three_winding_transformer.status_1 = 1
+    three_winding_transformer.status_2 = 1
+    three_winding_transformer.status_3 = 1
+    grid.append(three_winding_transformer)
+
+    assert 1 == len(grid.three_winding_transformer)
+    assert grid.graphs.active_graph.has_branch(102, 103)
+    assert grid.graphs.active_graph.has_branch(102, 104)
+    assert grid.graphs.active_graph.has_branch(103, 104)
+
+
+def test_grid_delete_three_winding_transformer(grid_with_3wt: Grid):
+    grid = grid_with_3wt
+    assert grid.graphs.active_graph.has_branch(101, 102)
+    assert grid.graphs.active_graph.has_branch(101, 103)
+    assert grid.graphs.active_graph.has_branch(102, 103)
+
+    grid.delete_branch3(branch=grid.three_winding_transformer[0])
+
+    assert 0 == len(grid.three_winding_transformer)
+
+    assert not grid.graphs.active_graph.has_branch(101, 102)
+    assert not grid.graphs.active_graph.has_branch(101, 103)
+    assert not grid.graphs.active_graph.has_branch(102, 103)
+
+
 def test_grid_activate_branch(basic_grid: Grid):
     grid = basic_grid