Voltage level topology model conversion

iidm/iidm-api/src/main/java/com/powsybl/iidm/network/VoltageLevel.java

@@ -1355,6 +1355,15 @@ default void remove() {
      */
     BusView getBusView();
 
+    /**
+     * Convert the topology model to another one. Notice that when converting from a
+     * node/breaker model to a bus/breaker model, we definitely lost some information as
+     * we are converting to a simpler topology model.
+     *
+     * @param newTopologyKind the new topology model kind
+     */
+    void convertToTopology(TopologyKind newTopologyKind);
+
     /**
      * Print an ASCII representation of the topology on the standard ouput.
      */

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/AbstractConnectable.java

@@ -132,7 +132,7 @@ public void allocateVariantArrayElement(int[] indexes, int sourceIndex) {
         }
     }
 
-    protected void move(TerminalExt oldTerminal, TopologyPoint oldTopologyPoint, int node, String voltageLevelId) {
+    protected void move(TerminalExt oldTerminal, int node, String voltageLevelId) {
         VoltageLevelExt voltageLevel = getNetwork().getVoltageLevel(voltageLevelId);
         if (voltageLevel == null) {
             throw new PowsyblException("Voltage level '" + voltageLevelId + "' not found");
@@ -152,10 +152,10 @@ protected void move(TerminalExt oldTerminal, TopologyPoint oldTopologyPoint, int
                 .build();
 
         // detach the terminal from its previous voltage level
-        attachTerminal(oldTerminal, oldTopologyPoint, voltageLevel, terminalExt);
+        replaceTerminal(oldTerminal, voltageLevel.getTopologyModel(), terminalExt, true);
     }
 
-    protected void move(TerminalExt oldTerminal, TopologyPoint oldTopologyPoint, String busId, boolean connected) {
+    protected void move(TerminalExt oldTerminal, String busId, boolean connected) {
         Bus bus = getNetwork().getBusBreakerView().getBus(busId);
         if (bus == null) {
             throw new PowsyblException("Bus '" + busId + "' not found");
@@ -175,22 +175,43 @@ protected void move(TerminalExt oldTerminal, TopologyPoint oldTopologyPoint, Str
                 .build();
 
         // detach the terminal from its previous voltage level
-        attachTerminal(oldTerminal, oldTopologyPoint, (VoltageLevelExt) bus.getVoltageLevel(), terminalExt);
+        replaceTerminal(oldTerminal, ((VoltageLevelExt) bus.getVoltageLevel()).getTopologyModel(), terminalExt, true);
     }
 
-    private void attachTerminal(TerminalExt oldTerminal, TopologyPoint oldTopologyPoint, VoltageLevelExt voltageLevel, TerminalExt terminalExt) {
+    void replaceTerminal(TerminalExt oldTerminal, TopologyPoint oldTopologyPoint, TerminalExt newTerminalExt, boolean notify) {
+        Objects.requireNonNull(oldTerminal);
+        Objects.requireNonNull(newTerminalExt);
+        int iSide = terminals.indexOf(oldTerminal);
+        if (iSide == -1) {
+            throw new PowsyblException("Terminal to replace not found");
+        }
+        terminals.set(iSide, newTerminalExt);
+
+        if (notify) {
+            notifyUpdate("terminal" + (iSide + 1), oldTopologyPoint, newTerminalExt.getTopologyPoint());
+        }
+    }
+
+    void replaceTerminal(TerminalExt oldTerminal, TopologyModel newTopologyModel, TerminalExt newTerminalExt, boolean notify) {
+        Objects.requireNonNull(oldTerminal);
+        Objects.requireNonNull(newTopologyModel);
+        Objects.requireNonNull(newTerminalExt);
+
         // first, attach new terminal to connectable and to voltage level of destination, to ensure that the new terminal is valid
-        terminalExt.setConnectable(this);
-        voltageLevel.getTopologyModel().attach(terminalExt, false);
+        newTerminalExt.setConnectable(this);
+        newTopologyModel.attach(newTerminalExt, false);
 
         // then we can detach the old terminal, as we now know that the new terminal is valid
+        TopologyPoint oldTopologyPoint = oldTerminal.getTopologyPoint();
         oldTerminal.getVoltageLevel().getTopologyModel().detach(oldTerminal);
 
         // replace the old terminal by the new terminal in the connectable
-        int iSide = terminals.indexOf(oldTerminal);
-        terminals.set(iSide, terminalExt);
+        replaceTerminal(oldTerminal, oldTopologyPoint, newTerminalExt, notify);
 
-        notifyUpdate("terminal" + (iSide + 1), oldTopologyPoint, terminalExt.getTopologyPoint());
+        // also update terminal referrers
+        for (Referrer<Terminal> referrer : oldTerminal.getReferrerManager().getReferrers()) {
+            referrer.onReferencedReplacement(oldTerminal, newTerminalExt);
+        }
     }
 
     @Override

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/AbstractIidmExtension.java

@@ -25,4 +25,9 @@ public void onReferencedRemoval(Terminal removedTerminal) {
         // nothing by default
         // this is the place for terminal reference cleanup
     }
+
+    @Override
+    public void onReferencedReplacement(Terminal oldReferenced, Terminal newReferenced) {
+        // nothing by default
+    }
 }

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/AreaBoundaryImpl.java

@@ -17,13 +17,13 @@
 
 public class AreaBoundaryImpl implements AreaBoundary {
 
-    final Area area;
+    private final Area area;
 
-    final Terminal terminal;
+    private Terminal terminal;
 
-    final Boundary boundary;
+    private final Boundary boundary;
 
-    final boolean ac;
+    private final boolean ac;
 
     AreaBoundaryImpl(Area area, Terminal terminal, boolean ac) {
         this.area = Objects.requireNonNull(area);
@@ -68,4 +68,12 @@ public double getP() {
     public double getQ() {
         return boundary != null ? boundary.getQ() : terminal.getQ();
     }
+
+    void replaceTerminal(Terminal oldTerminal, Terminal newTerminal) {
+        Objects.requireNonNull(oldTerminal);
+        Objects.requireNonNull(newTerminal);
+        if (terminal == oldTerminal) {
+            terminal = newTerminal;
+        }
+    }
 }

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/AreaImpl.java

@@ -34,9 +34,31 @@ public class AreaImpl extends AbstractIdentifiable<Area> implements Area {
 
     private final TDoubleArrayList interchangeTarget;
 
-    private final Referrer<Terminal> terminalReferrer = this::removeAreaBoundary;
+    private final Referrer<Terminal> terminalReferrer = new Referrer<>() {
+        @Override
+        public void onReferencedRemoval(Terminal terminal) {
+            removeAreaBoundary(terminal);
+        }
+
+        @Override
+        public void onReferencedReplacement(Terminal oldTerminal, Terminal newTerminal) {
+            for (AreaBoundary areaBoundary : areaBoundaries) {
+                ((AreaBoundaryImpl) areaBoundary).replaceTerminal(oldTerminal, newTerminal);
+            }
+        }
+    };
 
-    private final Referrer<Boundary> boundaryReferrer = this::removeAreaBoundary;
+    private final Referrer<Boundary> boundaryReferrer = new Referrer<>() {
+        @Override
+        public void onReferencedRemoval(Boundary boundary) {
+            removeAreaBoundary(boundary);
+        }
+
+        @Override
+        public void onReferencedReplacement(Boundary oldBoundary, Boundary newBoundary) {
+            // cannot happen
+        }
+    };
 
     AreaImpl(Ref<NetworkImpl> ref, Ref<SubnetworkImpl> subnetworkRef, String id, String name, boolean fictitious, String areaType,
                     double interchangeTarget) {

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/BusBreakerTopologyModel.java

@@ -100,7 +100,8 @@ public Switch add() {
             }
 
             SwitchImpl aSwitch = new SwitchImpl(voltageLevel, id, getName(), isFictitious(), SwitchKind.BREAKER, open, true);
-            addSwitch(aSwitch, busId1, busId2);
+            getNetwork().getIndex().checkAndAdd(aSwitch);
+            addSwitchToTopology(aSwitch, busId1, busId2);
             getNetwork().getListeners().notifyCreation(aSwitch);
             return aSwitch;
         }
@@ -797,10 +798,9 @@ private void removeAllBuses() {
         removedBusesIds.forEach(id -> network.getListeners().notifyAfterRemoval(id));
     }
 
-    private void addSwitch(SwitchImpl aSwitch, String busId1, String busId2) {
+    void addSwitchToTopology(SwitchImpl aSwitch, String busId1, String busId2) {
         int v1 = getVertex(busId1, true);
         int v2 = getVertex(busId2, true);
-        getNetwork().getIndex().checkAndAdd(aSwitch);
         int e = graph.addEdge(v1, v2, aSwitch);
         switches.put(aSwitch.getId(), e);
     }

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/BusTerminal.java

@@ -41,7 +41,7 @@ public void moveConnectable(int node, String voltageLevelId) {
             if (removed) {
                 throw new PowsyblException(UNMODIFIABLE_REMOVED_EQUIPMENT + connectable.id);
             }
-            getConnectable().move(BusTerminal.this, getTopologyPoint(), node, voltageLevelId);
+            getConnectable().move(BusTerminal.this, node, voltageLevelId);
         }
     };
 
@@ -87,7 +87,7 @@ public void moveConnectable(String busId, boolean connected) {
             if (removed) {
                 throw new PowsyblException(UNMODIFIABLE_REMOVED_EQUIPMENT + connectable.id);
             }
-            getConnectable().move(BusTerminal.this, getTopologyPoint(), busId, connected);
+            getConnectable().move(BusTerminal.this, busId, connected);
         }
 
     };

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/NodeBreakerTopologyModel.java

@@ -626,6 +626,16 @@ CalculatedBusTopology getCalculatedBusTopology() {
         return variants.get().calculatedBusTopology;
     }
 
+    void removeSwitchFromTopology(String switchId, boolean notify) {
+        Integer e = switches.get(switchId);
+        if (e == null) {
+            throw new PowsyblException("Switch '" + switchId
+                    + "' not found in voltage level '" + voltageLevel.getId() + "'");
+        }
+        graph.removeEdge(e, notify);
+        graph.removeIsolatedVertices(notify);
+    }
+
     private final VoltageLevelExt.NodeBreakerViewExt nodeBreakerView = new VoltageLevelExt.NodeBreakerViewExt() {
 
         private final TIntObjectMap<TDoubleArrayList> fictitiousP0ByNode = TCollections.synchronizedMap(new TIntObjectHashMap<>());
@@ -873,13 +883,7 @@ public int getSwitchCount() {
 
         @Override
         public void removeSwitch(String switchId) {
-            Integer e = switches.get(switchId);
-            if (e == null) {
-                throw new PowsyblException("Switch '" + switchId
-                        + "' not found in voltage level '" + voltageLevel.getId() + "'");
-            }
-            graph.removeEdge(e);
-            graph.removeIsolatedVertices();
+            NodeBreakerTopologyModel.this.removeSwitchFromTopology(switchId, true);
         }
 
         @Override

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/NodeTerminal.java

@@ -53,7 +53,7 @@ public void moveConnectable(int node, String voltageLevelId) {
             if (removed) {
                 throw new PowsyblException(UNMODIFIABLE_REMOVED_EQUIPMENT + connectable.id);
             }
-            getConnectable().move(NodeTerminal.this, getTopologyPoint(), node, voltageLevelId);
+            getConnectable().move(NodeTerminal.this, node, voltageLevelId);
         }
     };
 
@@ -89,7 +89,7 @@ public void moveConnectable(String busId, boolean connected) {
             if (removed) {
                 throw new PowsyblException(UNMODIFIABLE_REMOVED_EQUIPMENT + connectable.id);
             }
-            getConnectable().move(NodeTerminal.this, getTopologyPoint(), busId, connected);
+            getConnectable().move(NodeTerminal.this, busId, connected);
         }
 
     };

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/Referrer.java

@@ -20,4 +20,14 @@ public interface Referrer<T> {
      * @param removedReferenced The referenced that has been removed from the network.
      */
     void onReferencedRemoval(T removedReferenced);
+
+    /**
+     * Called when a referenced object is replaced with another one. Implementations of this method
+     * should handle any required updates or transfers necessary when the referenced object is
+     * replaced.
+     *
+     * @param oldReferenced The original referenced object that is being replaced.
+     * @param newReferenced The new referenced object that is taking the place of the old one.
+     */
+    void onReferencedReplacement(T oldReferenced, T newReferenced);
 }

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/RegulatingPoint.java

@@ -164,4 +164,11 @@ public void onReferencedRemoval(Terminal removedTerminal) {
             regulationMode.fill(0, regulationMode.size(), StaticVarCompensator.RegulationMode.OFF.ordinal());
         }
     }
+
+    @Override
+    public void onReferencedReplacement(Terminal oldReferenced, Terminal newReferenced) {
+        if (regulatingTerminal == oldReferenced) {
+            regulatingTerminal = (TerminalExt) newReferenced;
+        }
+    }
 }

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/VoltageLevelImpl.java

@@ -10,8 +10,8 @@
 import com.google.common.collect.Lists;
 import com.google.common.primitives.Ints;
 import com.powsybl.commons.PowsyblException;
-import com.powsybl.iidm.network.*;
 import com.powsybl.commons.ref.Ref;
+import com.powsybl.iidm.network.*;
 import com.powsybl.iidm.network.util.ShortIdDictionary;
 
 import java.io.IOException;
@@ -39,7 +39,7 @@ class VoltageLevelImpl extends AbstractIdentifiable<VoltageLevel> implements Vol
 
     private double highVoltageLimit;
 
-    private final AbstractTopologyModel topologyModel;
+    private AbstractTopologyModel topologyModel;
 
     /** Areas associated to this VoltageLevel, with at most one area for each area type */
     private final Set<Area> areas = new LinkedHashSet<>();
@@ -618,4 +618,83 @@ public void allocateVariantArrayElement(int[] indexes, int sourceIndex) {
         super.allocateVariantArrayElement(indexes, sourceIndex);
         topologyModel.allocateVariantArrayElement(indexes, sourceIndex);
     }
+
+    private void convertToBusBreakerModel() {
+        BusBreakerTopologyModel newTopologyModel = new BusBreakerTopologyModel(this);
+
+        // remove busbar sections because not needed in a bus/breaker topology
+        for (BusbarSection bbs : topologyModel.getNodeBreakerView().getBusbarSections()) {
+            bbs.remove();
+        }
+
+        for (Bus bus : topologyModel.getBusBreakerView().getBuses()) {
+            // no notification, this is just a mutation of a calculation bus to a configured bus
+            ConfiguredBusImpl configuredBus = new ConfiguredBusImpl(bus.getId(), bus.getOptionalName().orElse(null), bus.isFictitious(), this);
+            newTopologyModel.addBus(configuredBus);
+        }
+
+        // transfer retained switches
+        for (Switch sw : topologyModel.getBusBreakerView().getSwitchStream().toList()) {
+            String busId1 = topologyModel.getBusBreakerView().getBus1(sw.getId()).getId();
+            String busId2 = topologyModel.getBusBreakerView().getBus2(sw.getId()).getId();
+            // no notification, this is just a transfer
+            ((NodeBreakerTopologyModel) topologyModel).removeSwitchFromTopology(sw.getId(), false);
+            newTopologyModel.addSwitchToTopology((SwitchImpl) sw, busId1, busId2);
+        }
+
+        // reconnect all connectable to new topology model
+        // first store all bus/breaker topological infos associated to this terminal because we will start moving
+        // terminal from old mode to new one, it will modify the old topology model
+        record TopologyModelInfos(TerminalExt terminal, String connectableBusId, boolean connected) {
+        }
+        List<TopologyModelInfos> oldTopologyModelInfos = new ArrayList<>();
+        for (Terminal oldTerminal : topologyModel.getTerminals()) {
+            Bus connectableBus = oldTerminal.getBusBreakerView().getConnectableBus();
+            String connectableBusId = connectableBus == null ? null : connectableBus.getId();
+            boolean connected = oldTerminal.isConnected();
+            oldTopologyModelInfos.add(new TopologyModelInfos((TerminalExt) oldTerminal, connectableBusId, connected));
+        }
+
+        for (var infos : oldTopologyModelInfos) {
+            TerminalExt oldTerminalExt = infos.terminal();
+
+            // if there is no way to find a connectable bus, remove the connectable
+            // an alternative would be to connect them all to a new trash configured bus
+            if (infos.connectableBusId() == null) {
+                // here keep the removal notification
+                oldTerminalExt.getConnectable().remove();
+                continue;
+            }
+
+            AbstractConnectable<?> connectable = oldTerminalExt.getConnectable();
+
+            // create the new terminal with new type
+            TerminalExt newTerminalExt = new TerminalBuilder(networkRef, this, oldTerminalExt.getSide())
+                    .setBus(infos.connected ? infos.connectableBusId() : null)
+                    .setConnectableBus(infos.connectableBusId())
+                    .build();
+
+            connectable.replaceTerminal(oldTerminalExt, newTopologyModel, newTerminalExt, false);
+        }
+
+        // also here keep the notification for remaining switches removal
+        topologyModel.removeTopology();
+
+        TopologyKind oldTopologyKind = topologyModel.getTopologyKind();
+        topologyModel = newTopologyModel;
+
+        notifyUpdate("topologyKind", oldTopologyKind, TopologyKind.BUS_BREAKER);
+    }
+
+    @Override
+    public void convertToTopology(TopologyKind newTopologyKind) {
+        Objects.requireNonNull(newTopologyKind);
+        if (newTopologyKind != topologyModel.getTopologyKind()) {
+            if (newTopologyKind == TopologyKind.NODE_BREAKER) {
+                throw new PowsyblException("Topology model conversion from bus/breaker to node/breaker not yet supported");
+            } else if (newTopologyKind == TopologyKind.BUS_BREAKER) {
+                convertToBusBreakerModel();
+            }
+        }
+    }
 }

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/extensions/RemoteReactivePowerControlImpl.java

@@ -132,6 +132,13 @@ public void onReferencedRemoval(Terminal removedTerminal) {
         getExtendable().removeExtension(RemoteReactivePowerControl.class);
     }
 
+    @Override
+    public void onReferencedReplacement(Terminal oldReferenced, Terminal newReferenced) {
+        if (regulatingTerminal == oldReferenced) {
+            regulatingTerminal = newReferenced;
+        }
+    }
+
     @Override
     public void cleanup() {
         if (regulatingTerminal != null) {