diff --git a/power-grid-model-ds/solutions/advanced_4_build_new_substation.py b/power-grid-model-ds/solutions/advanced_4_build_new_substation.py
index 1ea9f8e..a047024 100644
--- a/power-grid-model-ds/solutions/advanced_4_build_new_substation.py
+++ b/power-grid-model-ds/solutions/advanced_4_build_new_substation.py
@@ -1,13 +1,22 @@
-from power_grid_model_ds import PowerGridModelInterface
-
-def check_for_capacity_issues(grid: Grid) -> LineArray:
-    """Check for capacity issues on the grid.
-    Return the lines that with capacity issues.
+def build_new_substation(grid: Grid, location: tuple[float, float]) -> NodeArray:
+    """Build a new substation at the given location.
+    Return the new substation.
     """
-    pgm_interface = PowerGridModelInterface(grid)
-    pgm_interface.calculate_power_flow()
-    pgm_interface.update_grid()
+    new_substation = MyNodeArray(
+        node_type=[NodeType.SUBSTATION_NODE.value],
+        u_rated=[10500.0],
+        x=[location[0]],
+        y=[location[1]]
+    )
+    grid.append(new_substation)
 
-    return grid.line[grid.line.is_overloaded]
+    new_source = SourceArray(
+        node=[new_substation.id.item()],
+        status=[1],
+        u_ref=[1],
+    )
+    grid.append(new_source)
+    return new_substation
 
-print(check_for_capacity_issues(grid))
+# 🏗️ Add a new substation at (400, 400)
+new_substation = build_new_substation(grid, (400, 400))
\ No newline at end of file