fix changing regulation for phaseTapChanger

src/main/java/org/gridsuite/modification/modifications/TwoWindingsTransformerModification.java

@@ -376,6 +376,14 @@ private static void setPhaseTapChangerRegulationAttributes(PhaseTapChanger phase
         // the order is important if regulation mode is set and regulation value or target dead band is null it will crash
         PhaseTapChanger.RegulationMode regulationMode = regulationModeModification == null ? null : regulationModeModification.getValue();
         String fieldName = (regulationMode == CURRENT_LIMITER) ? "Value" : "Flow set point";
+        // TODO implement some entity to modify all element at once in powsybl core/network store
+        // it is a fix to avoid to set regulation value to negative before setting regulation mode to ACTIVE_POWER_CONTROL
+        // so if a new mode is set, regulating is first set to false to pass all check and finally set to its true value
+        boolean previousRegulatingValue = isModification && phaseTapChanger.isRegulating();
+        if (isModification && phaseTapChanger.isRegulating()) {
+            phaseTapChanger.setRegulating(false);
+        }
+
         // Regulation value
         ReportNode regulationValueReportNode = ModificationUtils.getInstance().applyElementaryModificationsAndReturnReport(
             isModification ? phaseTapChanger::setRegulationValue : phaseTapChangerAdder::setRegulationValue,
@@ -405,11 +413,15 @@ private static void setPhaseTapChangerRegulationAttributes(PhaseTapChanger phase
         // Regulating
         ReportNode regulatingReportNode = ModificationUtils.getInstance().applyElementaryModificationsAndReturnReport(
             isModification ? phaseTapChanger::setRegulating : phaseTapChangerAdder::setRegulating,
-            isModification ? phaseTapChanger::isRegulating : () -> null,
+            isModification ? () -> previousRegulatingValue : () -> null,
             regulatingModification, "Phase tap regulating");
         if (regulationReports != null && regulatingReportNode != null) {
             regulationReports.add(regulatingReportNode);
         }
+        // fix because can not modify several elements at once
+        if (isModification && regulatingModification == null && previousRegulatingValue) {
+            phaseTapChanger.setRegulating(true);
+        }
     }
 
     private void processRatioTapChanger(Network network,

src/test/java/org/gridsuite/modification/modifications/TwoWindingsTransformerModificationTest.java

@@ -1023,5 +1023,42 @@ void testProcessPhaseTapChangerRegulationModification() {
                 regulationActivePowerControlModeModification, regulationValueModification, null, regulatingModification, regulationReports));
     }
 
+    @Test
+    void testProcessPhaseTapChangerRegulationModificationWithRegulating() {
+        TwoWindingsTransformer twt = createTwoWindingsTransformer(getNetwork().getSubstation("s1"), "trf3", "trf3", 2.0, 14.745, 0.0, 3.2E-5, 400.0, 225.0,
+                41, 151, getNetwork().getVoltageLevel("v1").getId(), getNetwork().getVoltageLevel("v2").getId(),
+                "trf3", 1, ConnectablePosition.Direction.TOP,
+                "trf3", 2, ConnectablePosition.Direction.TOP);
+        PhaseTapChangerAdder adder = twt.newPhaseTapChanger();
+        preparePhaseTapChangerAdder(adder);
+        adder.add();
+        PhaseTapChanger phaseTapChanger = twt.getPhaseTapChanger();
+
+        phaseTapChanger.setRegulationValue(100);
+        phaseTapChanger.setTargetDeadband(0);
+        phaseTapChanger.setRegulationMode(PhaseTapChanger.RegulationMode.CURRENT_LIMITER);
+        phaseTapChanger.setRegulating(true);
+
+        List<ReportNode> regulationReports = new ArrayList<>();
+        AttributeModification<PhaseTapChanger.RegulationMode> regulationActivePowerControlModeModification = new AttributeModification<>(
+                PhaseTapChanger.RegulationMode.ACTIVE_POWER_CONTROL, OperationType.SET);
+        AttributeModification<Double> regulationValueModification = new AttributeModification<>(-100.0, OperationType.SET);
+
+        processPhaseTapRegulation(phaseTapChanger, null, true,
+                regulationActivePowerControlModeModification, regulationValueModification, null, null, regulationReports);
+        assertEquals(-100.0, phaseTapChanger.getRegulationValue());
+        assertEquals(PhaseTapChanger.RegulationMode.ACTIVE_POWER_CONTROL, phaseTapChanger.getRegulationMode());
+        assertTrue(phaseTapChanger.isRegulating());
+
+        AttributeModification<PhaseTapChanger.RegulationMode> regulationCurrentLimiterModeModification = new AttributeModification<>(
+                PhaseTapChanger.RegulationMode.CURRENT_LIMITER, OperationType.SET);
+        AttributeModification<Double> regulationValueModification2 = new AttributeModification<>(100.0, OperationType.SET);
+        processPhaseTapRegulation(phaseTapChanger, null, true,
+                regulationCurrentLimiterModeModification, regulationValueModification2, null, null, regulationReports);
+        assertEquals(100.0, phaseTapChanger.getRegulationValue());
+        assertEquals(PhaseTapChanger.RegulationMode.CURRENT_LIMITER, phaseTapChanger.getRegulationMode());
+        assertTrue(phaseTapChanger.isRegulating());
+    }
+
 }