Fix shunt compensator component type (#419)

Signed-off-by: Geoffroy Jamgotchian <geoffroy.jamgotchian@rte-france.com>

single-line-diagram-core/src/main/java/com/powsybl/sld/builders/NetworkGraphBuilder.java

@@ -182,6 +182,19 @@ private void addSnakeEdges(SubstationGraph graph, Substation substation) {
                 .collect(Collectors.toList()));
     }
 
+    static boolean isCapacitor(ShuntCompensator sc) {
+        switch (sc.getModelType()) {
+            case LINEAR:
+                return ((ShuntCompensatorLinearModel) sc.getModel()).getBPerSection() >= 0;
+            case NON_LINEAR:
+                ShuntCompensatorNonLinearModel model = (ShuntCompensatorNonLinearModel) sc.getModel();
+                double averageB = model.getAllSections().stream().mapToDouble(ShuntCompensatorNonLinearModel.Section::getB).average().orElse(0);
+                return averageB >= 0;
+            default:
+                throw new IllegalStateException("Unknown shunt compensator model type: " + sc.getModelType());
+        }
+    }
+
     private abstract static class AbstractGraphBuilder extends DefaultTopologyVisitor {
 
         protected final VoltageLevelGraph graph;
@@ -219,8 +232,7 @@ private FeederNode createFeederNode(VoltageLevelGraph graph, Injection<?> inject
                 case STATIC_VAR_COMPENSATOR:
                     return NodeFactory.createStaticVarCompensator(graph, injection.getId(), injection.getNameOrId());
                 case SHUNT_COMPENSATOR:
-                    // FIXME(mathbagu): Non linear shunt can be capacitor or inductor depending on the number of section enabled
-                    return ((ShuntCompensator) injection).getB() >= 0 ? NodeFactory.createCapacitor(graph, injection.getId(), injection.getNameOrId())
+                    return isCapacitor((ShuntCompensator) injection) ? NodeFactory.createCapacitor(graph, injection.getId(), injection.getNameOrId())
                             : NodeFactory.createInductor(graph, injection.getId(), injection.getNameOrId());
                 case DANGLING_LINE:
                     return NodeFactory.createDanglingLine(graph, injection.getId(), injection.getNameOrId());

single-line-diagram-core/src/test/java/com/powsybl/sld/builders/NetworkGraphBuilderTest.java

@@ -0,0 +1,54 @@
+/**
+ * Copyright (c) 2022, 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.sld.builders;
+
+import com.powsybl.iidm.network.*;
+import com.powsybl.iidm.network.test.EurostagTutorialExample1Factory;
+import org.junit.Test;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * @author Geoffroy Jamgotchian <geoffroy.jamgotchian at rte-france.com>
+ */
+public class NetworkGraphBuilderTest {
+
+    @Test
+    public void isCapacitorTest() {
+        Network network = EurostagTutorialExample1Factory.create();
+        VoltageLevel vlload = network.getVoltageLevel("VLLOAD");
+        ShuntCompensator sc = vlload.newShuntCompensator()
+                .setId("SC")
+                .setConnectableBus("NLOAD")
+                .newLinearModel()
+                .setBPerSection(0.05)
+                .setMaximumSectionCount(1)
+                .add()
+                .setSectionCount(0)
+                .add();
+        assertTrue(NetworkGraphBuilder.isCapacitor(sc));
+        sc.getModel(ShuntCompensatorLinearModel.class).setBPerSection(-0.03);
+        assertFalse(NetworkGraphBuilder.isCapacitor(sc));
+        ShuntCompensator sc2 = vlload.newShuntCompensator()
+                .setId("SC2")
+                .setConnectableBus("NLOAD")
+                .newNonLinearModel()
+                .beginSection()
+                .setB(0.05)
+                .endSection()
+                .beginSection()
+                .setB(-0.02)
+                .endSection()
+                .add()
+                .setSectionCount(0)
+                .add();
+        assertTrue(NetworkGraphBuilder.isCapacitor(sc2));
+        sc2.getModel(ShuntCompensatorNonLinearModel.class).getAllSections().get(1).setB(-0.07);
+        assertFalse(NetworkGraphBuilder.isCapacitor(sc2));
+    }
+}