From 6fbe6063c42f449b54394c9377707c27afd4d488 Mon Sep 17 00:00:00 2001
From: Xavier Weiss <xavierw@kth.se>
Date: Wed, 6 Nov 2024 16:26:54 +0100
Subject: [PATCH] Add: Backend-Agnostic Detachment Check

Signed-off-by: Xavier Weiss <xavierw@kth.se>
---
 .../13_DetachmentOfLoadsAndGenerators.ipynb   | 32 +++++++++++++++++--
 grid2op/Backend/backend.py                    | 23 +++++++------
 grid2op/Backend/pandaPowerBackend.py          |  1 +
 3 files changed, 45 insertions(+), 11 deletions(-)

diff --git a/getting_started/13_DetachmentOfLoadsAndGenerators.ipynb b/getting_started/13_DetachmentOfLoadsAndGenerators.ipynb
index c5522a1d..1d01ce17 100644
--- a/getting_started/13_DetachmentOfLoadsAndGenerators.ipynb
+++ b/getting_started/13_DetachmentOfLoadsAndGenerators.ipynb
@@ -4,8 +4,8 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "### Shedding\n",
-    "In emergency conditions, it may be possible / necessary for a grid operator to disconnect certain loads, generators, or other components in order to prevent a larger blackout. This notebook explores how this can be achieved in Grid2OP. \n",
+    "### Detachment of Loads and Generators\n",
+    "In emergency conditions, it may be possible / necessary for a grid operator to detach certain loads, generators, or other components in order to prevent a larger blackout. This notebook explores how this can be achieved in Grid2OP. \n",
     "\n",
     "By default shedding is disabled in all environments, to provide the keyword argument allow_detachment when initializing the environment."
    ]
@@ -71,6 +71,34 @@
     ")\n",
     "display(network.res_line.loc[:, [\"p_from_mw\", \"p_to_mw\", \"q_from_mvar\", \"q_to_mvar\"]])"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "env.backend.loads_info()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "env.backend.generators_info()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "topo_vect = env.backend.get_topo_vect()\n",
+    "topo_vect[env.backend.load_pos_topo_vect]"
+   ]
   }
  ],
  "metadata": {
diff --git a/grid2op/Backend/backend.py b/grid2op/Backend/backend.py
index d843edb8..87d76738 100644
--- a/grid2op/Backend/backend.py
+++ b/grid2op/Backend/backend.py
@@ -1080,16 +1080,21 @@ def _runpf_with_diverging_exception(self, is_dc : bool) -> Optional[Exception]:
         conv = False
         exc_me = None
 
-        # if not self.allow_detachment and (~self._grid.load["in_service"]).any():
-        #     # TODO see if there is a better way here -> do not handle this here, but rather in Backend._next_grid_state
-        #     raise pp.powerflow.LoadflowNotConverged("Disconnected load: for now grid2op cannot handle properly"
-        #                                             " disconnected load. If you want to disconnect one, say it"
-        #                                             " consumes 0. instead. Please check loads: "
-        #                                             f"{(~self._grid.load['in_service'].values).nonzero()[0]}"
-        #                                             )
         try:
-            # load_p, load_q, load_v = self.loads_info()
-            # prod_p, prod_q, prod_v = self.generators_info()
+            # Check if loads/gens have been detached and if this is allowed, otherwise raise an error
+            # .. versionadded:: 1.11.0
+            topo_vect = self.get_topo_vect()
+            
+            load_buses = topo_vect[self.load_pos_topo_vect]
+            if not self.allow_detachment and (load_buses == -1).any():
+                raise Grid2OpException(f"One or more loads were detached before powerflow in Backend {type(self).__name__}"
+                                        "but this is not allowed or not supported (Game Over)")
+
+            gen_buses = topo_vect[self.gen_pos_topo_vect]
+            if not self.allow_detachment and (gen_buses == -1).any():
+                raise Grid2OpException(f"One or more generators were detached before powerflow in Backend {type(self).__name__}"
+                                        "but this is not allowed or not supported (Game Over)")
+            
             conv, exc_me = self.runpf(is_dc=is_dc)  # run powerflow
         except Grid2OpException as exc_:
             exc_me = exc_
diff --git a/grid2op/Backend/pandaPowerBackend.py b/grid2op/Backend/pandaPowerBackend.py
index 82477f25..9bf85f27 100644
--- a/grid2op/Backend/pandaPowerBackend.py
+++ b/grid2op/Backend/pandaPowerBackend.py
@@ -344,6 +344,7 @@ def load_grid(self,
 
         """
         self.can_handle_more_than_2_busbar()
+        self.can_handle_detachment()
         full_path = self.make_complete_path(path, filename)
 
         with warnings.catch_warnings():