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Security Analysis state monitored results for zero impedance branches in zero impedance mode #1298

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Security Analysis state monitored results for zero impedance branches in zero impedance mode #1298

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de62208
Unit test
Hadrien-Godard Nov 14, 2025
29560e5
Asserts
Hadrien-Godard Nov 20, 2025
fbf39e3
computeZeroImpedanceFlows in LfBranchImpl
Hadrien-Godard Nov 20, 2025
52fc064
Use zeroImpedanceFlows map
Hadrien-Godard Dec 3, 2025
ff0cd25
Refacto
Hadrien-Godard Dec 8, 2025
df4411a
T3WT
Hadrien-Godard Dec 8, 2025
66d1089
Refacto
Hadrien-Godard Dec 8, 2025
eaafb51
Reduce complexity
Hadrien-Godard Dec 8, 2025
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10 changes: 5 additions & 5 deletions src/main/java/com/powsybl/openloadflow/OpenLoadFlowProvider.java
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Expand Up @@ -116,7 +116,7 @@ private void updateAcState(Network network, LoadFlowParameters parameters, OpenL
result.getNetwork().updateState(updateParameters);

// zero or low impedance branch flows computation
computeZeroImpedanceFlows(result.getNetwork(), LoadFlowModel.AC);
computeZeroImpedanceFlows(result.getNetwork(), LoadFlowModel.AC, parameters.getDcPowerFactor());
}
} finally {
if (parametersExt.isNetworkCacheEnabled()) {
Expand Down Expand Up @@ -197,10 +197,10 @@ private static ReferenceBusAndSlackBusesResults buildReferenceBusAndSlackBusesRe
private record ReferenceBusAndSlackBusesResults(String referenceBusId, List<LoadFlowResult.SlackBusResult> slackBusResultList) {
}

private void computeZeroImpedanceFlows(LfNetwork network, LoadFlowModel loadFlowModel) {
private void computeZeroImpedanceFlows(LfNetwork network, LoadFlowModel loadFlowModel, double dcPowerFactor) {
for (LfZeroImpedanceNetwork zeroImpedanceNetwork : network.getZeroImpedanceNetworks(loadFlowModel)) {
new ZeroImpedanceFlows(zeroImpedanceNetwork.getGraph(), zeroImpedanceNetwork.getSpanningTree(), loadFlowModel)
.compute();
new ZeroImpedanceFlows(zeroImpedanceNetwork.getGraph(), zeroImpedanceNetwork.getSpanningTree(), loadFlowModel, dcPowerFactor)
.computeWithFlowsUpdate();
}
}

Expand Down Expand Up @@ -240,7 +240,7 @@ private LoadFlowResult.ComponentResult processResult(Network network, DcLoadFlow
result.getNetwork().updateState(updateParameters);

// zero or low impedance branch flows computation
computeZeroImpedanceFlows(result.getNetwork(), LoadFlowModel.DC);
computeZeroImpedanceFlows(result.getNetwork(), LoadFlowModel.DC, parameters.getDcPowerFactor());
}

var referenceBusAndSlackBusesResults = buildReferenceBusAndSlackBusesResults(result);
Expand Down
12 changes: 7 additions & 5 deletions src/main/java/com/powsybl/openloadflow/network/LfBranch.java
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Expand Up @@ -17,10 +17,7 @@
import com.powsybl.openloadflow.util.Evaluable;
import com.powsybl.security.results.BranchResult;

import java.util.Collections;
import java.util.List;
import java.util.Objects;
import java.util.Optional;
import java.util.*;

/**
* @author Geoffroy Jamgotchian {@literal <geoffroy.jamgotchian at rte-france.com>}
Expand All @@ -38,6 +35,9 @@ enum BranchType {
TIE_LINE
}

record LfBranchResults(double p1, double p2, double q1, double q2, double i1, double i2) {
}

class LfLimit {

private final String name;
Expand Down Expand Up @@ -261,7 +261,9 @@ default List<LfLimit> getLimits2(LimitType type, LimitReductionManager limitRedu

boolean isTransformerReactivePowerControlled();

List<BranchResult> createBranchResult(double preContingencyBranchP1, double preContingencyBranchOfContingencyP1, boolean createExtension);
List<BranchResult> createBranchResult(double preContingencyBranchP1, double preContingencyBranchOfContingencyP1,
boolean createExtension, Map<String, LfBranchResults> zeroImpedanceFlows,
LoadFlowModel loadFlowModel);

double computeApparentPower1();

Expand Down
26 changes: 26 additions & 0 deletions src/main/java/com/powsybl/openloadflow/network/impl/AbstractImpedantLfBranch.java
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Expand Up @@ -11,9 +11,12 @@
import com.powsybl.iidm.network.TwoSides;
import com.powsybl.openloadflow.network.*;
import com.powsybl.openloadflow.util.Evaluable;
import com.powsybl.openloadflow.util.PerUnit;
import com.powsybl.security.results.BranchResult;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Objects;

import static com.powsybl.openloadflow.util.EvaluableConstants.NAN;
Expand Down Expand Up @@ -498,4 +501,27 @@ protected double getAngle1() {
protected double getAngle2() {
return getBus2() != null ? getBus2().getAngle() : Double.NaN;
}

protected LfBranchResults getImpedantLfBranchResults() {
return new LfBranchResults(p1.eval(), p2.eval(), q1.eval(), q2.eval(), i1.eval(), i2.eval());
}

protected BranchResult buildBranchResult(LoadFlowModel loadFlowModel, Map<String, LfBranchResults> zeroImpedanceFlows, double currentScale1, double currentScale2,
double preContingencyBranchP1, double preContingencyBranchOfContingencyP1) {
LfBranchResults lfBranchResults = this.isZeroImpedance(loadFlowModel) ? zeroImpedanceFlows.get(this.getId())
: getImpedantLfBranchResults();

double flowP1 = lfBranchResults.p1() * PerUnit.SB;
double flowQ1 = lfBranchResults.q1() * PerUnit.SB;
double flowP2 = lfBranchResults.p2() * PerUnit.SB;
double flowQ2 = lfBranchResults.q2() * PerUnit.SB;
double currentI1 = lfBranchResults.i1() * currentScale1;
double currentI2 = lfBranchResults.i2() * currentScale2;

double flowTransfer = Double.NaN;
if (!Double.isNaN(preContingencyBranchP1) && !Double.isNaN(preContingencyBranchOfContingencyP1)) {
flowTransfer = (flowP1 - preContingencyBranchP1) / preContingencyBranchOfContingencyP1;
}
return new BranchResult(getId(), flowP1, flowQ1, currentI1, flowP2, flowQ2, currentI2, flowTransfer);
}
}
12 changes: 5 additions & 7 deletions src/main/java/com/powsybl/openloadflow/network/impl/LfBranchImpl.java
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Expand Up @@ -210,16 +210,14 @@ public boolean hasPhaseControllerCapability() {
}

@Override
public List<BranchResult> createBranchResult(double preContingencyBranchP1, double preContingencyBranchOfContingencyP1, boolean createExtension) {
public List<BranchResult> createBranchResult(double preContingencyBranchP1, double preContingencyBranchOfContingencyP1,
boolean createExtension, Map<String, LfBranch.LfBranchResults> zeroImpedanceFlows,
LoadFlowModel loadFlowModel) {
var branch = getBranch();
double flowTransfer = Double.NaN;
if (!Double.isNaN(preContingencyBranchP1) && !Double.isNaN(preContingencyBranchOfContingencyP1)) {
flowTransfer = (p1.eval() * PerUnit.SB - preContingencyBranchP1) / preContingencyBranchOfContingencyP1;
}
double currentScale1 = PerUnit.ib(branch.getTerminal1().getVoltageLevel().getNominalV());
double currentScale2 = PerUnit.ib(branch.getTerminal2().getVoltageLevel().getNominalV());
var branchResult = new BranchResult(getId(), p1.eval() * PerUnit.SB, q1.eval() * PerUnit.SB, currentScale1 * i1.eval(),
p2.eval() * PerUnit.SB, q2.eval() * PerUnit.SB, currentScale2 * i2.eval(), flowTransfer);

var branchResult = buildBranchResult(loadFlowModel, zeroImpedanceFlows, currentScale1, currentScale2, preContingencyBranchP1, preContingencyBranchOfContingencyP1);
if (createExtension) {
branchResult.addExtension(OlfBranchResult.class, new OlfBranchResult(piModel.getR1(), piModel.getContinuousR1(),
getV1() * branch.getTerminal1().getVoltageLevel().getNominalV(),
Expand Down
8 changes: 5 additions & 3 deletions src/main/java/com/powsybl/openloadflow/network/impl/LfDanglingLineBranch.java
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Expand Up @@ -17,6 +17,7 @@
import com.powsybl.security.results.BranchResult;

import java.util.List;
import java.util.Map;
import java.util.Objects;

/**
Expand Down Expand Up @@ -70,12 +71,13 @@ public boolean hasPhaseControllerCapability() {
}

@Override
public List<BranchResult> createBranchResult(double preContingencyBranchP1, double preContingencyBranchOfContingencyP1, boolean createExtension) {
public List<BranchResult> createBranchResult(double preContingencyBranchP1, double preContingencyBranchOfContingencyP1,
boolean createExtension, Map<String, LfBranchResults> zeroImpedanceFlows,
LoadFlowModel loadFlowModel) {
// in a security analysis, we don't have any way to monitor the flows at boundary side. So in the branch result,
// we follow the convention side 1 for network side and side 2 for boundary side.
double currentScale = PerUnit.ib(getDanglingLine().getTerminal().getVoltageLevel().getNominalV());
return List.of(new BranchResult(getId(), p1.eval() * PerUnit.SB, q1.eval() * PerUnit.SB, currentScale * i1.eval(),
p2.eval() * PerUnit.SB, q2.eval() * PerUnit.SB, currentScale * i2.eval(), Double.NaN));
return List.of(buildBranchResult(loadFlowModel, zeroImpedanceFlows, currentScale, currentScale, Double.NaN, Double.NaN));
}

@Override
Expand Down
35 changes: 29 additions & 6 deletions src/main/java/com/powsybl/openloadflow/network/impl/LfLegBranch.java
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Expand Up @@ -33,7 +33,7 @@ private LfLegBranch(LfNetwork network, LfBus bus1, LfBus bus0, PiModel piModel,
this.legRef = Ref.create(leg, parameters.isCacheEnabled());
}

private ThreeWindingsTransformer getTwt() {
public ThreeWindingsTransformer getTwt() {
return twtRef.get();
}

Expand Down Expand Up @@ -139,7 +139,9 @@ public boolean hasPhaseControllerCapability() {
}

@Override
public List<BranchResult> createBranchResult(double preContingencyBranchP1, double preContingencyBranchOfContingencyP1, boolean createExtension) {
public List<BranchResult> createBranchResult(double preContingencyBranchP1, double preContingencyBranchOfContingencyP1,
boolean createExtension, Map<String, LfBranch.LfBranchResults> zeroImpedanceFlows,
LoadFlowModel loadFlowModel) {
throw new PowsyblException("Unsupported type of branch for branch result: " + getId());
}

Expand Down Expand Up @@ -201,18 +203,39 @@ public void updateFlows(double p1, double q1, double p2, double q2) {
.setQ(q1 * PerUnit.SB);
}

public static ThreeWindingsTransformerResult createThreeWindingsTransformerResult(LfNetwork network, String threeWindingsTransformerId, boolean createResultExtension) {
private static LfBranchResults extractLegBranchResults(LfLegBranch leg) {
return new LfBranchResults(leg.p1.eval(), Double.NaN, leg.q1.eval(), Double.NaN, leg.i1.eval(), Double.NaN);
}

public static ThreeWindingsTransformerResult createThreeWindingsTransformerResult(LfNetwork network, String threeWindingsTransformerId, boolean createResultExtension,
Map<String, LfBranch.LfBranchResults> zeroImpedanceFlows, LoadFlowModel loadFlowModel) {
LfLegBranch leg1 = (LfLegBranch) network.getBranchById(LfLegBranch.getId(threeWindingsTransformerId, 1));
LfLegBranch leg2 = (LfLegBranch) network.getBranchById(LfLegBranch.getId(threeWindingsTransformerId, 2));
LfLegBranch leg3 = (LfLegBranch) network.getBranchById(LfLegBranch.getId(threeWindingsTransformerId, 3));

double i1Base = PerUnit.ib(leg1.legRef.get().getTerminal().getVoltageLevel().getNominalV());
double i2Base = PerUnit.ib(leg2.legRef.get().getTerminal().getVoltageLevel().getNominalV());
double i3Base = PerUnit.ib(leg3.legRef.get().getTerminal().getVoltageLevel().getNominalV());

LfBranchResults legBranchResults1 = leg1.isZeroImpedance(loadFlowModel) ? zeroImpedanceFlows.get(leg1.getId())
: extractLegBranchResults(leg1);
LfBranchResults legBranchResults2 = leg2.isZeroImpedance(loadFlowModel) ? zeroImpedanceFlows.get(leg2.getId())
: extractLegBranchResults(leg2);
LfBranchResults legBranchResults3 = leg3.isZeroImpedance(loadFlowModel) ? zeroImpedanceFlows.get(leg3.getId())
: extractLegBranchResults(leg3);

double flowP1 = legBranchResults1.p1() * PerUnit.SB;
double flowP2 = legBranchResults2.p1() * PerUnit.SB;
double flowP3 = legBranchResults3.p1() * PerUnit.SB;
double flowQ1 = legBranchResults1.q1() * PerUnit.SB;
double flowQ2 = legBranchResults2.q1() * PerUnit.SB;
double flowQ3 = legBranchResults3.q1() * PerUnit.SB;
double currentI1 = legBranchResults1.i1() * i1Base;
double currentI2 = legBranchResults2.i1() * i2Base;
double currentI3 = legBranchResults3.i1() * i3Base;

ThreeWindingsTransformerResult result = new ThreeWindingsTransformerResult(threeWindingsTransformerId,
leg1.getP1().eval() * PerUnit.SB, leg1.getQ1().eval() * PerUnit.SB, leg1.getI1().eval() * i1Base,
leg2.getP1().eval() * PerUnit.SB, leg2.getQ1().eval() * PerUnit.SB, leg2.getI1().eval() * i2Base,
leg3.getP1().eval() * PerUnit.SB, leg3.getQ1().eval() * PerUnit.SB, leg3.getI1().eval() * i3Base);
flowP1, flowQ1, currentI1, flowP2, flowQ2, currentI2, flowP3, flowQ3, currentI3);

if (createResultExtension) {
result.addExtension(OlfThreeWindingsTransformerResult.class, new OlfThreeWindingsTransformerResult(
Expand Down
5 changes: 4 additions & 1 deletion src/main/java/com/powsybl/openloadflow/network/impl/LfSwitch.java
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Expand Up @@ -21,6 +21,7 @@

import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Objects;

import static com.powsybl.openloadflow.util.EvaluableConstants.NAN;
Expand Down Expand Up @@ -359,7 +360,9 @@ public List<Evaluable> getAdditionalClosedQ2() {
}

@Override
public List<BranchResult> createBranchResult(double preContingencyBranchP1, double preContingencyBranchOfContingencyP1, boolean createExtension) {
public List<BranchResult> createBranchResult(double preContingencyBranchP1, double preContingencyBranchOfContingencyP1,
boolean createExtension, Map<String, LfBranchResults> zeroImpedanceFlows,
LoadFlowModel loadFlowModel) {
throw new PowsyblException("Unsupported type of branch for branch result: " + getSwitch().getId());
}

Expand Down
20 changes: 9 additions & 11 deletions src/main/java/com/powsybl/openloadflow/network/impl/LfTieLineBranch.java
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Expand Up @@ -14,6 +14,7 @@
import com.powsybl.security.results.BranchResult;

import java.util.List;
import java.util.Map;
import java.util.Objects;

/**
Expand Down Expand Up @@ -75,21 +76,18 @@ public DanglingLine getHalf2() {
}

@Override
public List<BranchResult> createBranchResult(double preContingencyBranchP1, double preContingencyBranchOfContingencyP1, boolean createExtension) {
double flowTransfer = Double.NaN;
if (!Double.isNaN(preContingencyBranchP1) && !Double.isNaN(preContingencyBranchOfContingencyP1)) {
flowTransfer = (p1.eval() * PerUnit.SB - preContingencyBranchP1) / preContingencyBranchOfContingencyP1;
}
public List<BranchResult> createBranchResult(double preContingencyBranchP1, double preContingencyBranchOfContingencyP1,
boolean createExtension, Map<String, LfBranchResults> zeroImpedanceFlows,
LoadFlowModel loadFlowModel) {
double nominalV1 = getHalf1().getTerminal().getVoltageLevel().getNominalV();
double nominalV2 = getHalf2().getTerminal().getVoltageLevel().getNominalV();
double currentScale1 = PerUnit.ib(nominalV1);
double currentScale2 = PerUnit.ib(nominalV2);
var branchResult = new BranchResult(getId(), p1.eval() * PerUnit.SB, q1.eval() * PerUnit.SB, currentScale1 * i1.eval(),
p2.eval() * PerUnit.SB, q2.eval() * PerUnit.SB, currentScale2 * i2.eval(), flowTransfer);
var half1Result = new BranchResult(getHalf1().getId(), p1.eval() * PerUnit.SB, q1.eval() * PerUnit.SB, currentScale1 * i1.eval(),
Double.NaN, Double.NaN, Double.NaN, flowTransfer);
var half2Result = new BranchResult(getHalf2().getId(), p2.eval() * PerUnit.SB, q2.eval() * PerUnit.SB, currentScale2 * i2.eval(),
Double.NaN, Double.NaN, Double.NaN, flowTransfer);

var branchResult = buildBranchResult(loadFlowModel, zeroImpedanceFlows, currentScale1, currentScale2, preContingencyBranchP1, preContingencyBranchOfContingencyP1);

var half1Result = new BranchResult(getHalf1().getId(), branchResult.getP1(), branchResult.getQ1(), branchResult.getI1(), Double.NaN, Double.NaN, Double.NaN, branchResult.getFlowTransfer());
var half2Result = new BranchResult(getHalf2().getId(), branchResult.getP2(), branchResult.getQ2(), branchResult.getI2(), Double.NaN, Double.NaN, Double.NaN, branchResult.getFlowTransfer());
if (createExtension) {
branchResult.addExtension(OlfBranchResult.class, new OlfBranchResult(piModel.getR1(), piModel.getContinuousR1(),
getV1() * nominalV1, getV2() * nominalV2, Math.toDegrees(getAngle1()), Math.toDegrees(getAngle2())));
Expand Down
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