diff --git a/cgmes/cgmes-model/src/main/java/com/powsybl/cgmes/model/WindingType.java b/cgmes/cgmes-model/src/main/java/com/powsybl/cgmes/model/WindingType.java
index 918ee5ef6ae..244507730db 100644
--- a/cgmes/cgmes-model/src/main/java/com/powsybl/cgmes/model/WindingType.java
+++ b/cgmes/cgmes-model/src/main/java/com/powsybl/cgmes/model/WindingType.java
@@ -15,7 +15,7 @@
  */
 public enum WindingType {
 
-    PRIMARY, SECONDARY, TERTIARY;
+    PRIMARY, SECONDARY, TERTIARY, UNKNOWN;
 
     /**
      * Retrieve the WindingType for the given transformer winding/end.
@@ -25,23 +25,21 @@ public enum WindingType {
     public static WindingType windingType(PropertyBag end) {
         if (end.containsKey("windingType")) {
             // For CIM14 (CIM ENTSOE Profile1) primary is determined by TransformerWinding.windingType
-            String wtype = end.getLocal("windingType");
-            if (wtype.endsWith("WindingType.primary")) {
-                return WindingType.PRIMARY;
-            } else if (wtype.endsWith("WindingType.secondary")) {
-                return WindingType.SECONDARY;
-            } else if (wtype.endsWith("WindingType.tertiary")) {
-                return WindingType.TERTIARY;
-            }
+            return switch (end.getLocal("windingType")) {
+                case "WindingType.primary" -> WindingType.PRIMARY;
+                case "WindingType.secondary" -> WindingType.SECONDARY;
+                case "WindingType.tertiary" -> WindingType.TERTIARY;
+                default -> WindingType.UNKNOWN;
+            };
         } else if (end.containsKey("endNumber")) {
             // For CIM16 (CGMES 2.4.15) primary is defined by TransformerEnd.endNumber
             try {
                 return WindingType.values()[end.asInt("endNumber") - 1];
             } catch (Exception e) {
-                return WindingType.PRIMARY;
+                return WindingType.UNKNOWN;
             }
         }
-        return WindingType.PRIMARY;
+        return WindingType.UNKNOWN;
     }
 
     /**
diff --git a/cgmes/cgmes-model/src/test/java/com/powsybl/cgmes/model/WindingTypeTest.java b/cgmes/cgmes-model/src/test/java/com/powsybl/cgmes/model/WindingTypeTest.java
index e613ad651a5..c1c23839e55 100644
--- a/cgmes/cgmes-model/src/test/java/com/powsybl/cgmes/model/WindingTypeTest.java
+++ b/cgmes/cgmes-model/src/test/java/com/powsybl/cgmes/model/WindingTypeTest.java
@@ -46,8 +46,8 @@ void cim14WindingTypeTest() {
 
         end4 = new PropertyBag(Collections.singletonList(WINDING_TYPE), true);
         end4.put(WINDING_TYPE, "WindingType.quaternary");
-        assertEquals(WindingType.PRIMARY, WindingType.windingType(end4));
-        assertEquals(1, WindingType.endNumber(end4));
+        assertEquals(WindingType.UNKNOWN, WindingType.windingType(end4));
+        assertEquals(4, WindingType.endNumber(end4));
     }
 
     @Test
@@ -69,7 +69,7 @@ void cim16WindingTypeTest() {
 
         end4 = new PropertyBag(Collections.singletonList(END_NUMBER), true);
         end4.put(END_NUMBER, "4");
-        assertEquals(WindingType.PRIMARY, WindingType.windingType(end4));
-        assertEquals(1, WindingType.endNumber(end4));
+        assertEquals(WindingType.UNKNOWN, WindingType.windingType(end4));
+        assertEquals(4, WindingType.endNumber(end4));
     }
 }