Fix flow decomposition loss compensation when dangling lines have shu…

…nt susceptance (#160) * fix losses compensation when dangling lines have shunt susceptance Signed-off-by: Caio Luke <caioluke97@gmail.com>
powsybl · Sep 20, 2024 · 4e4c5e8 · 4e4c5e8
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diff --git a/docs/flow_decomposition/algorithm-description.md b/docs/flow_decomposition/algorithm-description.md
@@ -27,7 +27,8 @@ These losses are then compensated on the sending side of each network element.
 ![Losses compensation on lines](/_static/img/flow_decomposition/lossesCompensationOnLine.svg)
 
 A special treatment is done on tie lines, where instead of compensating the losses on the sending terminal, losses are
-compensated at both sides proportionally to the resistance of each half line.
+compensated at both sides. Losses are calculated for each half line individually by adding its terminal and boundary flows.
+If the half lines have no shunt susceptance, this corresponds to split tie line losses proportionally to the resistance of each half line.
 
 ![Losses compensation on tie lines](/_static/img/flow_decomposition/lossesCompensationOnTieLine.svg)
 

diff --git a/flow-decomposition/src/main/java/com/powsybl/flow_decomposition/LossesCompensator.java b/flow-decomposition/src/main/java/com/powsybl/flow_decomposition/LossesCompensator.java
@@ -112,15 +112,12 @@ private void compensateLossesOnBranch(Network network, Branch<?> branch) {
     }
 
     private void compensateLossesOnTieLine(Network network, TieLine tieLine) {
-        double r1 = tieLine.getDanglingLine1().getR();
-        double r2 = tieLine.getDanglingLine2().getR();
-        double r = r1 + r2;
-        Terminal terminal1 = tieLine.getDanglingLine1().getTerminal();
-        Terminal terminal2 = tieLine.getDanglingLine2().getTerminal();
-        double losses = terminal1.getP() + terminal2.getP();
-        double lossesSide1 = losses * r1 / r;
-        double lossesSide2 = losses * r2 / r;
-
+        DanglingLine danglingLine1 = tieLine.getDanglingLine1();
+        DanglingLine danglingLine2 = tieLine.getDanglingLine2();
+        Terminal terminal1 = danglingLine1.getTerminal();
+        Terminal terminal2 = danglingLine2.getTerminal();
+        double lossesSide1 = terminal1.getP() + danglingLine1.getBoundary().getP();
+        double lossesSide2 = terminal2.getP() + danglingLine2.getBoundary().getP();
         updateLoadForLossesOnTerminal(network, terminal1, lossesSide1);
         updateLoadForLossesOnTerminal(network, terminal2, lossesSide2);
     }

diff --git a/flow-decomposition/src/test/java/com/powsybl/flow_decomposition/LossesCompensationTests.java b/flow-decomposition/src/test/java/com/powsybl/flow_decomposition/LossesCompensationTests.java
@@ -7,10 +7,7 @@
 package com.powsybl.flow_decomposition;
 
 import com.powsybl.flow_decomposition.xnec_provider.XnecProviderByIds;
-import com.powsybl.iidm.network.Bus;
-import com.powsybl.iidm.network.Country;
-import com.powsybl.iidm.network.Load;
-import com.powsybl.iidm.network.Network;
+import com.powsybl.iidm.network.*;
 import com.powsybl.loadflow.LoadFlow;
 import com.powsybl.loadflow.LoadFlowParameters;
 import org.junit.jupiter.api.Test;
@@ -106,6 +103,10 @@ void checkThatLossesCompensationOnTieLineDoesDispatchLossesProportionallyToEachS
         LossesCompensator lossesCompensator = new LossesCompensator(FlowDecompositionParameters.DISABLE_LOSSES_COMPENSATION_EPSILON);
         lossesCompensator.run(network);
 
+        TieLine tieLine = network.getTieLine("FGEN1 11 X     11 1 + X     11 BLOAD 11 1");
+        assertEquals(0.0, tieLine.getDanglingLine1().getB(), EPSILON);
+        assertEquals(0.0, tieLine.getDanglingLine2().getB(), EPSILON);
+
         Load lossesFgenBload = network.getLoad("LOSSES FGEN1 11 X     11 1 + X     11 BLOAD 11 1");
         assertNull(lossesFgenBload);
 
@@ -119,6 +120,33 @@ void checkThatLossesCompensationOnTieLineDoesDispatchLossesProportionallyToEachS
         assertEquals(0.046875, lossesBloadX.getP0(), EPSILON);
     }
 
+    @Test
+    void checkThatLossesCompensationOnTieLineDoesDispatchLossesProportionallyToEachSideResistanceWithB() {
+        String networkFileName = "NETWORK_SINGLE_LOAD_TWO_GENERATORS_WITH_XNODE.uct";
+
+        Network network = importNetwork(networkFileName);
+        TieLine tieLine = network.getTieLine("FGEN1 11 X     11 1 + X     11 BLOAD 11 1");
+        tieLine.getDanglingLine1().setB(1E-3);
+        tieLine.getDanglingLine2().setB(1E-3);
+        LoadFlowParameters loadFlowParameters = new LoadFlowParameters();
+        loadFlowParameters.setDc(AC_LOAD_FLOW);
+        LoadFlow.run(network, loadFlowParameters);
+        LossesCompensator lossesCompensator = new LossesCompensator(FlowDecompositionParameters.DISABLE_LOSSES_COMPENSATION_EPSILON);
+        lossesCompensator.run(network);
+
+        Load lossesFgenBload = network.getLoad("LOSSES FGEN1 11 X     11 1 + X     11 BLOAD 11 1");
+        assertNull(lossesFgenBload);
+
+        Load lossesFgenX = network.getLoad("LOSSES FGEN1 11");
+        assertNotNull(lossesFgenX);
+        assertEquals("FGEN1 1", lossesFgenX.getTerminal().getVoltageLevel().getId());
+        assertEquals(0.044098, lossesFgenX.getP0(), EPSILON);
+        Load lossesBloadX = network.getLoad("LOSSES BLOAD 11");
+        assertNotNull(lossesBloadX);
+        assertEquals("BLOAD 1", lossesBloadX.getTerminal().getVoltageLevel().getId());
+        assertEquals(0.050000, lossesBloadX.getP0(), EPSILON);
+    }
+
     @Test
     void checkThatDefaultFlowDecompositionDoesNotCompensateLosses() {
         String networkFileName = "NETWORK_SINGLE_LOAD_TWO_GENERATORS_WITH_COUNTRIES_EXTRA_SUBSTATION.uct";