Introduce hvdc state save and restore for AC emulation after continge…

…ncy (#688)

Signed-off-by: Anne Tilloy <anne.tilloy@rte-france.com>
Signed-off-by: Geoffroy Jamgotchian <geoffroy.jamgotchian@gmail.com>

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

@@ -0,0 +1,21 @@
+/**
+ * Copyright (c) 2023, RTE (http://www.rte-france.com)
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+package com.powsybl.openloadflow.network;
+
+/**
+ * @author Anne Tilloy <anne.tilloy at rte-france.com>
+ */
+public class HvdcState extends ElementState<LfHvdc> {
+
+    public HvdcState(LfHvdc hvdc) {
+        super(hvdc);
+    }
+
+    public static HvdcState save(LfHvdc hvdc) {
+        return new HvdcState(hvdc);
+    }
+}

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

@@ -23,22 +23,27 @@ public class NetworkState {
 
     private final List<BranchState> branchStates;
 
-    protected NetworkState(List<BusState> busStates, List<BranchState> branchStates) {
+    private final List<HvdcState> hvdcStates;
+
+    protected NetworkState(List<BusState> busStates, List<BranchState> branchStates, List<HvdcState> hvdcStates) {
         this.busStates = Objects.requireNonNull(busStates);
         this.branchStates = Objects.requireNonNull(branchStates);
+        this.hvdcStates = Objects.requireNonNull(hvdcStates);
     }
 
     public static NetworkState save(LfNetwork network) {
         Objects.requireNonNull(network);
         LOGGER.trace("Saving network state");
         List<BusState> busStates = ElementState.save(network.getBuses(), BusState::save);
         List<BranchState> branchStates = ElementState.save(network.getBranches(), BranchState::save);
-        return new NetworkState(busStates, branchStates);
+        List<HvdcState> hvdcStates = ElementState.save(network.getHvdcs(), HvdcState::save);
+        return new NetworkState(busStates, branchStates, hvdcStates);
     }
 
     public void restore() {
         LOGGER.trace("Restoring network state");
         ElementState.restore(busStates);
         ElementState.restore(branchStates);
+        ElementState.restore(hvdcStates);
     }
 }

src/test/java/com/powsybl/openloadflow/sensi/ac/AcSensitivityAnalysisContingenciesTest.java

@@ -1194,4 +1194,30 @@ void testPredefinedResults4() {
         assertEquals(0, result.getBranchFlow1SensitivityValue("l23", "l23", "l12"), LoadFlowAssert.DELTA_POWER);
         assertEquals(Double.NaN, result.getBranchFlow1SensitivityValue("l23", "l23", "l23"), LoadFlowAssert.DELTA_POWER);
     }
+
+    @Test
+    void testRestoreAfterContingencyOnHvdc() {
+        Network network = HvdcNetworkFactory.createWithHvdcInAcEmulation();
+        network.getGeneratorStream().forEach(gen -> gen.setMaxP(2 * gen.getMaxP()));
+        network.getHvdcLine("hvdc34").newExtension(HvdcAngleDroopActivePowerControlAdder.class)
+                .withDroop(180)
+                .withP0(0.f)
+                .withEnabled(true)
+                .add();
+
+        SensitivityAnalysisParameters sensiParameters = createParameters(false, "b1_vl_0", true);
+        sensiParameters.getLoadFlowParameters().getExtension(OpenLoadFlowParameters.class).setSlackBusPMaxMismatch(0.001);
+
+        List<SensitivityFactor> factors = createFactorMatrix(Stream.of("g1", "g5").map(network::getGenerator).collect(Collectors.toList()),
+                Stream.of("l12", "l25", "l56").map(network::getBranch).collect(Collectors.toList()));
+
+        List<Contingency> contingencies = List.of(new Contingency("hvdc34", new HvdcLineContingency("hvdc34")),
+                                                  new Contingency("l45", new BranchContingency("l45")));
+
+        SensitivityAnalysisResult result = sensiRunner.run(network, factors, contingencies, Collections.emptyList(), sensiParameters);
+
+        assertEquals(0.269, result.getBranchFlow1SensitivityValue("l45", "g1", "l12"), LoadFlowAssert.DELTA_POWER);
+        assertEquals(0.356, result.getBranchFlow1SensitivityValue("l45", "g1", "l25"), LoadFlowAssert.DELTA_POWER);
+        assertEquals(-0.144, result.getBranchFlow1SensitivityValue("l45", "g1", "l56"), LoadFlowAssert.DELTA_POWER);
+    }
 }