Added support of action to reconnect branch at both side action

src/main/java/com/powsybl/openloadflow/network/LfAction.java

@@ -212,10 +212,14 @@ private static Optional<LfAction> create(LfBranch branch, String actionId, boole
     private static Optional<LfAction> create(TerminalsConnectionAction action, LfNetwork lfNetwork) {
         LfBranch branch = lfNetwork.getBranchById(action.getElementId());
         if (branch != null) {
-            if (action.getSide().isEmpty() && action.isOpen()) {
-                return Optional.of(new LfAction(action.getId(), branch, null, null, null, null, null));
+            if (action.getSide().isEmpty()) {
+                if (action.isOpen()) {
+                    return Optional.of(new LfAction(action.getId(), branch, null, null, null, null, null));
+                } else {
+                    return Optional.of(new LfAction(action.getId(), null, branch, null, null, null, null));
+                }
             } else {
-                throw new UnsupportedOperationException("Line connection action: only open line at both sides is supported yet.");
+                throw new UnsupportedOperationException("Terminals connection action: only open or close branch at both sides is supported yet.");
             }
         }
         return Optional.empty(); // could be in another component

src/main/java/com/powsybl/openloadflow/network/LfTopoConfig.java

@@ -31,6 +31,8 @@ public class LfTopoConfig {
 
     private final Set<String> branchIdsOpenableSide2 = new HashSet<>();
 
+    private final Set<String> branchIdsToClose = new HashSet<>();
+
     public LfTopoConfig() {
         switchesToOpen = new HashSet<>();
         switchesToClose = new HashSet<>();
@@ -83,4 +85,8 @@ public Set<String> getBranchIdsOpenableSide1() {
     public Set<String> getBranchIdsOpenableSide2() {
         return branchIdsOpenableSide2;
     }
+
+    public Set<String> getBranchIdsToClose() {
+        return branchIdsToClose;
+    }
 }

src/main/java/com/powsybl/openloadflow/network/impl/Networks.java

@@ -124,15 +124,23 @@ private static void retainAndCloseNecessarySwitches(Network network, LfTopoConfi
                 .forEach(sw -> sw.setRetained(true));
 
         topoConfig.getSwitchesToClose().forEach(sw -> sw.setOpen(false)); // in order to be present in the network.
+        topoConfig.getBranchIdsToClose().stream().map(network::getBranch).forEach(branch -> {
+            branch.getTerminal1().connect();
+            branch.getTerminal2().connect();
+        }); // in order to be present in the network.
     }
 
-    private static void restoreInitialTopology(LfNetwork network, Set<Switch> allSwitchesToClose) {
+    private static void restoreInitialTopology(LfNetwork network, Set<Switch> allSwitchesToClose, Set<String> branchIdsToClose) {
         var connectivity = network.getConnectivity();
         connectivity.startTemporaryChanges();
         allSwitchesToClose.stream().map(Identifiable::getId).forEach(id -> {
             LfBranch branch = network.getBranchById(id);
             connectivity.removeEdge(branch);
         });
+        branchIdsToClose.stream().forEach(id -> {
+            LfBranch branch = network.getBranchById(id);
+            connectivity.removeEdge(branch);
+        });
         Set<LfBus> removedBuses = connectivity.getVerticesRemovedFromMainComponent();
         removedBuses.forEach(bus -> bus.setDisabled(true));
         Set<LfBranch> removedBranches = new HashSet<>(connectivity.getEdgesRemovedFromMainComponent());
@@ -182,10 +190,10 @@ public static LfNetworkList load(Network network, LfNetworkParameters networkPar
         } else {
             modifiedTopoConfig = topoConfig;
         }
-        if (!modifiedTopoConfig.isBreaker()) {
+        if (!modifiedTopoConfig.isBreaker() && modifiedTopoConfig.getBranchIdsToClose().isEmpty()) {
             return new LfNetworkList(load(network, topoConfig, networkParameters, reporter));
         } else {
-            if (!networkParameters.isBreakers()) {
+            if (!networkParameters.isBreakers() && modifiedTopoConfig.isBreaker()) {
                 throw new PowsyblException("LF networks have to be built from bus/breaker view");
             }
 
@@ -201,10 +209,10 @@ public static LfNetworkList load(Network network, LfNetworkParameters networkPar
 
             List<LfNetwork> lfNetworks = load(network, topoConfig, networkParameters, reporter);
 
-            if (!modifiedTopoConfig.getSwitchesToClose().isEmpty()) {
+            if (!(modifiedTopoConfig.getSwitchesToClose().isEmpty() && modifiedTopoConfig.getBranchIdsToClose().isEmpty())) {
                 for (LfNetwork lfNetwork : lfNetworks) {
                     // disable all buses and branches not connected to main component (because of switch to close)
-                    restoreInitialTopology(lfNetwork, modifiedTopoConfig.getSwitchesToClose());
+                    restoreInitialTopology(lfNetwork, modifiedTopoConfig.getSwitchesToClose(), modifiedTopoConfig.getBranchIdsToClose());
                 }
             }
 

src/main/java/com/powsybl/openloadflow/sa/AbstractSecurityAnalysis.java

@@ -13,8 +13,7 @@
 import com.powsybl.computation.ComputationManager;
 import com.powsybl.contingency.ContingenciesProvider;
 import com.powsybl.contingency.Contingency;
-import com.powsybl.iidm.network.Network;
-import com.powsybl.iidm.network.Switch;
+import com.powsybl.iidm.network.*;
 import com.powsybl.loadflow.LoadFlowParameters;
 import com.powsybl.loadflow.LoadFlowResult;
 import com.powsybl.math.matrix.MatrixFactory;
@@ -125,6 +124,10 @@ SecurityAnalysisReport runSync(SecurityAnalysisParameters securityAnalysisParame
         findAllPtcToOperate(actions, topoConfig);
         findAllRtcToOperate(actions, topoConfig);
 
+        // try to find branches (lines and two windings transformers).
+        // tie lines and three windings transformers missing.
+        findAllBranchesToClose(network, actions, topoConfig);
+
         // load contingencies
         List<Contingency> contingencies = contingenciesProvider.getContingencies(network);
         // try to find all switches impacted by at least one contingency and for each contingency the branches impacted
@@ -340,6 +343,21 @@ protected static void findAllRtcToOperate(List<Action> actions, LfTopoConfig top
         }
     }
 
+    protected static void findAllBranchesToClose(Network network, List<Action> actions, LfTopoConfig topoConfig) {
+        // only branches open at both side or open at one side are visible in the LfNetwork.
+        for (Action action : actions) {
+            if (TerminalsConnectionAction.NAME.equals(action.getType())) {
+                TerminalsConnectionAction terminalsConnectionAction = (TerminalsConnectionAction) action;
+                if (terminalsConnectionAction.getSide().isEmpty() && !terminalsConnectionAction.isOpen()) {
+                    Branch branch = network.getBranch(terminalsConnectionAction.getElementId());
+                    if (branch != null && !(branch instanceof TieLine)) {
+                        topoConfig.getBranchIdsToClose().add(terminalsConnectionAction.getElementId());
+                    }
+                }
+            }
+        }
+    }
+
     protected static void distributedMismatch(LfNetwork network, double mismatch, LoadFlowParameters loadFlowParameters,
                                            OpenLoadFlowParameters openLoadFlowParameters) {
         if (loadFlowParameters.isDistributedSlack() && Math.abs(mismatch) > 0) {

src/test/java/com/powsybl/openloadflow/sa/LfActionTest.java

@@ -83,7 +83,7 @@ void test() {
             assertTrue(LfAction.create(new TerminalsConnectionAction("A line action", "x", true), lfNetwork, network, acParameters.getNetworkParameters().isBreakers()).isEmpty());
             assertTrue(LfAction.create(new PhaseTapChangerTapPositionAction("A phase tap change action", "y", false, 3), lfNetwork, network, acParameters.getNetworkParameters().isBreakers()).isEmpty());
             var lineAction = new TerminalsConnectionAction("A line action", "L1", ThreeSides.ONE, false);
-            assertEquals("Line connection action: only open line at both sides is supported yet.", assertThrows(UnsupportedOperationException.class, () -> LfAction.create(lineAction, lfNetwork, network, acParameters.getNetworkParameters().isBreakers())).getMessage());
+            assertEquals("Terminals connection action: only open or close branch at both sides is supported yet.", assertThrows(UnsupportedOperationException.class, () -> LfAction.create(lineAction, lfNetwork, network, acParameters.getNetworkParameters().isBreakers())).getMessage());
         }
     }
 

src/test/java/com/powsybl/openloadflow/sa/OpenSecurityAnalysisWithActionsTest.java

@@ -1257,4 +1257,43 @@ void testVSCLossSetpoint() {
         assertEquals(-0.0, getPostContingencyResult(result, "contingency").getNetworkResult().getBranchResult("l34").getP1(), LoadFlowAssert.DELTA_POWER);
         assertEquals(-200.0, getOperatorStrategyResult(result, "strategy").getNetworkResult().getBranchResult("l34").getP1(), LoadFlowAssert.DELTA_POWER);
     }
+
+    @Test
+    void testTerminalsConnectionAction() {
+        Network network = FourBusNetworkFactory.create();
+        network.getLine("l23").getTerminal1().disconnect();
+        network.getLine("l23").getTerminal2().disconnect();
+        List<Contingency> contingencies = Stream.of("l14")
+                .map(id -> new Contingency(id, new BranchContingency(id)))
+                .collect(Collectors.toList());
+
+        List<Action> actions = List.of(new TerminalsConnectionAction("closeLine", "l23", false));
+        List<OperatorStrategy> operatorStrategies = List.of(new OperatorStrategy("strategyL1", ContingencyContext.specificContingency("l14"), new TrueCondition(), List.of("closeLine")));
+        List<StateMonitor> monitors = createAllBranchesMonitors(network);
+
+        LoadFlowParameters parameters = new LoadFlowParameters();
+        parameters.setDistributedSlack(true);
+        parameters.setDc(true);
+        SecurityAnalysisParameters securityAnalysisParameters = new SecurityAnalysisParameters();
+        securityAnalysisParameters.setLoadFlowParameters(parameters);
+
+        SecurityAnalysisResult result = runSecurityAnalysis(network, contingencies, monitors, securityAnalysisParameters,
+                operatorStrategies, actions, Reporter.NO_OP);
+        OperatorStrategyResult dcStrategyResult = getOperatorStrategyResult(result, "strategyL1");
+
+        assertEquals(0.333, dcStrategyResult.getNetworkResult().getBranchResult("l12").getP1(), LoadFlowAssert.DELTA_POWER);
+        assertEquals(1.333, dcStrategyResult.getNetworkResult().getBranchResult("l23").getP1(), LoadFlowAssert.DELTA_POWER);
+        assertEquals(-1.0, dcStrategyResult.getNetworkResult().getBranchResult("l34").getP1(), LoadFlowAssert.DELTA_POWER);
+
+        parameters.setDc(false);
+        SecurityAnalysisParameters securityAnalysisParametersAc = new SecurityAnalysisParameters();
+        securityAnalysisParametersAc.setLoadFlowParameters(parameters);
+        SecurityAnalysisResult resultAc = runSecurityAnalysis(network, contingencies, monitors, securityAnalysisParametersAc,
+                operatorStrategies, actions, Reporter.NO_OP);
+        OperatorStrategyResult acStrategyResult = getOperatorStrategyResult(resultAc, "strategyL1");
+
+        assertEquals(0.336, acStrategyResult.getNetworkResult().getBranchResult("l12").getP1(), LoadFlowAssert.DELTA_POWER);
+        assertEquals(1.332, acStrategyResult.getNetworkResult().getBranchResult("l23").getP1(), LoadFlowAssert.DELTA_POWER);
+        assertEquals(-1.0, acStrategyResult.getNetworkResult().getBranchResult("l34").getP1(), LoadFlowAssert.DELTA_POWER);
+    }
 }