Support low impedance branches in adm matrix calculation

Signed-off-by: Geoffroy Jamgotchian <[email protected]>
powsybl · Nov 17, 2024 · bf94e9c · bf94e9c
1 parent 1557c2c
commit bf94e9c
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Showing 6 changed files with 47 additions and 43 deletions.
diff --git a/src/main/java/com/powsybl/openloadflow/RemoteVoltageTargetCheckerParameters.java b/src/main/java/com/powsybl/openloadflow/RemoteVoltageTargetCheckerParameters.java
@@ -8,7 +8,6 @@
 package com.powsybl.openloadflow;
 
 import com.powsybl.math.matrix.MatrixFactory;
-import com.powsybl.openloadflow.network.util.VoltageInitializer;
 
 import java.util.Objects;
 

diff --git a/src/main/java/com/powsybl/openloadflow/adm/AbstractAdmittanceEquationTerm.java b/src/main/java/com/powsybl/openloadflow/adm/AbstractAdmittanceEquationTerm.java
@@ -10,9 +10,7 @@
 import com.powsybl.openloadflow.equations.AbstractElementEquationTerm;
 import com.powsybl.openloadflow.equations.Variable;
 import com.powsybl.openloadflow.equations.VariableSet;
-import com.powsybl.openloadflow.network.LfBranch;
-import com.powsybl.openloadflow.network.LfBus;
-import com.powsybl.openloadflow.network.PiModel;
+import com.powsybl.openloadflow.network.*;
 
 import java.util.List;
 import java.util.Objects;
@@ -67,18 +65,19 @@ protected AbstractAdmittanceEquationTerm(LfBranch branch, LfBus bus1, LfBus bus2
         variables = List.of(v1xVar, v2xVar, v1yVar, v2yVar);
 
         PiModel piModel = branch.getPiModel();
-        if (piModel.getX() == 0) {
-            throw new IllegalArgumentException("Branch '" + branch.getId() + "' has reactance equal to zero");
-        }
         rho = piModel.getR1();
-        if (piModel.getZ() == 0) {
-            throw new IllegalArgumentException("Branch '" + branch.getId() + "' has Z equal to zero");
-        }
-
-        r = piModel.getR();
-        x = piModel.getX();
-        double z = Math.sqrt(r * r + x * x);
-        zInvSquare = 1 / (z * z);
+
+        piModel.getCutZ(LfNetworkParameters.LOW_IMPEDANCE_THRESHOLD_DEFAULT_VALUE, LoadFlowModel.AC).ifPresentOrElse(z -> {
+            r = z.getReal();
+            x = z.getImaginary();
+            double zMod = z.abs();
+            zInvSquare = 1 / (zMod * zMod);
+        }, () -> {
+            r = piModel.getR();
+            x = piModel.getX();
+            double z = Math.sqrt(r * r + x * x);
+            zInvSquare = 1 / (z * z);
+        });
 
         double alpha = piModel.getA1();
         cosA = Math.cos(Math.toRadians(alpha));

diff --git a/src/main/java/com/powsybl/openloadflow/adm/AdmittanceEquationSystem.java b/src/main/java/com/powsybl/openloadflow/adm/AdmittanceEquationSystem.java
@@ -9,10 +9,10 @@
 
 import com.powsybl.openloadflow.equations.EquationSystem;
 import com.powsybl.openloadflow.equations.VariableSet;
-import com.powsybl.openloadflow.network.*;
-import net.jafama.FastMath;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import com.powsybl.openloadflow.network.LfBranch;
+import com.powsybl.openloadflow.network.LfBus;
+import com.powsybl.openloadflow.network.LfNetwork;
+import com.powsybl.openloadflow.network.LfShunt;
 
 import java.util.Collection;
 import java.util.Objects;
@@ -23,8 +23,6 @@
  */
 public final class AdmittanceEquationSystem {
 
-    private static final Logger LOGGER = LoggerFactory.getLogger(AdmittanceEquationSystem.class);
-
     private static final double B_EPSILON = 1e-8;
 
     private final EquationSystem<AdmittanceVariableType, AdmittanceEquationType> equationSystem;
@@ -38,7 +36,7 @@ public EquationSystem<AdmittanceVariableType, AdmittanceEquationType> getEquatio
     }
 
     //Equations are created based on the branches connections
-    private static void createImpedantBranch(VariableSet<AdmittanceVariableType> variableSet, EquationSystem<AdmittanceVariableType, AdmittanceEquationType> equationSystem,
+    private static void createBranchEquation(VariableSet<AdmittanceVariableType> variableSet, EquationSystem<AdmittanceVariableType, AdmittanceEquationType> equationSystem,
                                              LfBranch branch, LfBus bus1, LfBus bus2) {
         if (bus1 != null && bus2 != null) {
             // Equation system Y*V = I (expressed in cartesian coordinates x,y)
@@ -60,15 +58,7 @@ private static void createBranchEquations(Collection<LfBranch> branches, Variabl
         for (LfBranch branch : branches) {
             LfBus bus1 = branch.getBus1();
             LfBus bus2 = branch.getBus2();
-            PiModel piModel = branch.getPiModel();
-            if (FastMath.abs(piModel.getX()) < LfNetworkParameters.LOW_IMPEDANCE_THRESHOLD_DEFAULT_VALUE) {
-                if (bus1 != null && bus2 != null) {
-                    LOGGER.warn("Non impedant branches ({}) not supported in admittance matrix",
-                            branch.getId());
-                }
-            } else {
-                createImpedantBranch(variableSet, equationSystem, branch, bus1, bus2);
-            }
+            createBranchEquation(variableSet, equationSystem, branch, bus1, bus2);
         }
     }
 

diff --git a/src/main/java/com/powsybl/openloadflow/network/PiModel.java b/src/main/java/com/powsybl/openloadflow/network/PiModel.java
@@ -8,6 +8,7 @@
 package com.powsybl.openloadflow.network;
 
 import org.apache.commons.lang3.Range;
+import org.apache.commons.math3.complex.Complex;
 
 import java.util.Optional;
 
@@ -68,6 +69,8 @@ public interface PiModel {
 
     Optional<Direction> updateTapPositionToReachNewA1(double deltaA1, int maxTapShift, AllowedDirection allowedDirection);
 
+    Optional<Complex> getCutZ(double minZ, LoadFlowModel loadFlowModel);
+
     boolean setMinZ(double minZ, LoadFlowModel loadFlowModel);
 
     void setBranch(LfBranch branch);

diff --git a/src/main/java/com/powsybl/openloadflow/network/PiModelArray.java b/src/main/java/com/powsybl/openloadflow/network/PiModelArray.java
@@ -8,6 +8,7 @@
 package com.powsybl.openloadflow.network;
 
 import org.apache.commons.lang3.Range;
+import org.apache.commons.math3.complex.Complex;
 
 import java.util.List;
 import java.util.Objects;
@@ -358,6 +359,11 @@ public Optional<Direction> updateTapPositionToReachNewA1(double deltaA1, int max
         return direction;
     }
 
+    @Override
+    public Optional<Complex> getCutZ(double minZ, LoadFlowModel loadFlowModel) {
+        return getModel().getCutZ(minZ, loadFlowModel);
+    }
+
     @Override
     public boolean setMinZ(double minZ, LoadFlowModel loadFlowModel) {
         boolean done = false;

diff --git a/src/main/java/com/powsybl/openloadflow/network/SimplePiModel.java b/src/main/java/com/powsybl/openloadflow/network/SimplePiModel.java
@@ -9,7 +9,9 @@
 
 import net.jafama.FastMath;
 import org.apache.commons.lang3.Range;
+import org.apache.commons.math3.complex.Complex;
 
+import java.util.Objects;
 import java.util.Optional;
 
 /**
@@ -171,27 +173,32 @@ public Optional<Direction> updateTapPositionToReachNewA1(double deltaA1, int max
         throw new IllegalStateException(NO_TAP_POSITION_ERROR);
     }
 
-    private void rescaleZ(double z) {
-        double ksi = getKsi();
-        r = z * FastMath.sin(ksi);
-        x = z * FastMath.cos(ksi);
-    }
-
     @Override
-    public boolean setMinZ(double minZ, LoadFlowModel loadFlowModel) {
+    public Optional<Complex> getCutZ(double minZ, LoadFlowModel loadFlowModel) {
+        Objects.requireNonNull(loadFlowModel);
         if (loadFlowModel == LoadFlowModel.DC) {
             if (FastMath.abs(this.x) < minZ) {
-                this.x = minZ;
-                return true;
+                return Optional.of(Complex.valueOf(0, minZ));
             }
         } else {
             double z = getZ();
             if (z < minZ) {
-                rescaleZ(minZ);
-                return true;
+                double ksi = getKsi();
+                double newR = minZ * FastMath.sin(ksi);
+                double newX = minZ * FastMath.cos(ksi);
+                return Optional.of(Complex.valueOf(newR, newX));
             }
         }
-        return false;
+        return Optional.empty();
+    }
+
+    @Override
+    public boolean setMinZ(double minZ, LoadFlowModel loadFlowModel) {
+        return getCutZ(minZ, loadFlowModel).map(z -> {
+            SimplePiModel.this.r = z.getReal();
+            SimplePiModel.this.x = z.getImaginary();
+            return true;
+        }).orElse(false);
     }
 
     @Override