diff --git a/src/main/java/com/powsybl/openloadflow/equations/TargetVector.java b/src/main/java/com/powsybl/openloadflow/equations/TargetVector.java
index 8a017b7a27..3632ac3f37 100644
--- a/src/main/java/com/powsybl/openloadflow/equations/TargetVector.java
+++ b/src/main/java/com/powsybl/openloadflow/equations/TargetVector.java
@@ -68,6 +68,15 @@ public void onTapPositionChange(LfBranch branch, int oldPosition, int newPositio
         public void onShuntSusceptanceChange(LfShunt shunt, double b) {
             invalidateValues();
         }
+
+        @Override
+        public void onDisableChange(LfElement element, boolean disabled) {
+            for (var equationTerm : equationSystem.getEquationTerms(element.getType(), element.getNum())) {
+                if (equationTerm.hasRhs()) {
+                    invalidateValues();
+                }
+            }
+        }
     };
 
     public TargetVector(LfNetwork network, EquationSystem<V, E> equationSystem, Initializer<V, E> initializer) {
diff --git a/src/test/java/com/powsybl/openloadflow/sa/OpenSecurityAnalysisTest.java b/src/test/java/com/powsybl/openloadflow/sa/OpenSecurityAnalysisTest.java
index 5db08c4323..e410eaa32c 100644
--- a/src/test/java/com/powsybl/openloadflow/sa/OpenSecurityAnalysisTest.java
+++ b/src/test/java/com/powsybl/openloadflow/sa/OpenSecurityAnalysisTest.java
@@ -3185,4 +3185,58 @@ void testLimitReductions() {
         assertEquals(1000., limitViolations.get(0).getLimit(), 0.0001);
         assertEquals(945.51416, limitViolations.get(0).getValue(), 0.0001);
     }
+
+    @Test
+    void testPhaseTapChangerContingency() {
+        Network network = PhaseControlFactory.createNetworkWithT2wt();
+        TwoWindingsTransformer pst = network.getTwoWindingsTransformer("PS1");
+        pst.getPhaseTapChanger().setTapPosition(2);
+
+        network.newLine().setId("L3")
+                .setConnectableBus1("B1")
+                .setBus1("B1")
+                .setConnectableBus2("B2")
+                .setBus2("B2")
+                .setR(4.0)
+                .setX(200.0)
+                .add();
+
+        network.newLine().setId("L4")
+                .setConnectableBus1("B3")
+                .setBus1("B3")
+                .setConnectableBus2("B2")
+                .setBus2("B2")
+                .setR(4.0)
+                .setX(200.0)
+                .add();
+
+        LoadFlowParameters lfParameters = new LoadFlowParameters()
+                .setDc(true);
+
+        List<Contingency> contingencies = List.of(Contingency.twoWindingsTransformer("PS1"));
+        List<StateMonitor> monitors = createAllBranchesMonitors(network);
+        SecurityAnalysisResult result = runSecurityAnalysis(network, contingencies, monitors, lfParameters);
+        // pre-contingency tests
+        PreContingencyResult preContingencyResult = result.getPreContingencyResult();
+        assertEquals(7.623, preContingencyResult.getNetworkResult().getBranchResult("L1").getP1(), LoadFlowAssert.DELTA_POWER);
+        assertEquals(56.503, preContingencyResult.getNetworkResult().getBranchResult("L2").getP1(), LoadFlowAssert.DELTA_POWER);
+        assertEquals(7.623, preContingencyResult.getNetworkResult().getBranchResult("L3").getP1(), LoadFlowAssert.DELTA_POWER);
+        assertEquals(28.252, preContingencyResult.getNetworkResult().getBranchResult("L4").getP1(), LoadFlowAssert.DELTA_POWER);
+        assertEquals(84.755, preContingencyResult.getNetworkResult().getBranchResult("PS1").getP1(), LoadFlowAssert.DELTA_POWER);
+        // post-contingency tests
+        PostContingencyResult ps1ContingencyResult = getPostContingencyResult(result, "PS1");
+        assertEquals(50.0, ps1ContingencyResult.getNetworkResult().getBranchResult("L1").getP1(), LoadFlowAssert.DELTA_POWER);
+        assertEquals(0.0, ps1ContingencyResult.getNetworkResult().getBranchResult("L2").getP1(), LoadFlowAssert.DELTA_POWER);
+        assertEquals(50.0, ps1ContingencyResult.getNetworkResult().getBranchResult("L3").getP1(), LoadFlowAssert.DELTA_POWER);
+        assertEquals(0.0, ps1ContingencyResult.getNetworkResult().getBranchResult("L4").getP1(), LoadFlowAssert.DELTA_POWER);
+
+        // we compare with a dc load flow
+        pst.getTerminal1().disconnect();
+        pst.getTerminal2().disconnect();
+        LoadFlow.run(network, lfParameters);
+        assertActivePowerEquals(50.0, network.getBranch("L1").getTerminal1());
+        assertActivePowerEquals(0.0, network.getBranch("L2").getTerminal1());
+        assertActivePowerEquals(50.0, network.getBranch("L3").getTerminal1());
+        assertActivePowerEquals(0.0, network.getBranch("L4").getTerminal1());
+    }
 }