Fix loading calculation of lines and transformers

roseau/load_flow_single/models/lines.py

@@ -260,27 +260,21 @@ def res_power_losses(self) -> Q_[Complex]:
 
     @property
     def res_loading(self) -> Q_[float] | None:
-        """Get the loading of the line (unitless)."""
-        amp = self._parameters._ampacity
-        if amp is None:
+        """The loading of the line (unitless) if ``self.parameters.ampacity`` is set, else ``None``."""
+        if (amp := self._parameters._ampacity) is None:
             return None
         current1, current2 = self._res_currents_getter(warning=True)
-        i_max = amp * self._max_loading
-        return Q_(max(abs(current1), abs(current2)) / i_max, "")
+        return Q_(max(abs(current1), abs(current2)) / amp, "")
 
     @property
     def res_violated(self) -> bool | None:
-        """Whether the line current exceeds the maximal current of the line (computed with the parameters' ampacities
-        and the maximal loading of the line itself).
+        """Whether the line current loading exceeds its maximal loading.
 
-        Returns ``None`` if the ampacities or the `max_loading` is not set are not set.
+        Returns ``None`` if the ``self.parameters.ampacity`` is not set.
         """
-        amp = self._parameters._ampacity
-        if amp is None:
+        if (loading := self.res_loading) is None:
             return None
-        current1, current2 = self._res_currents_getter(warning=True)
-        i_max = amp * self._max_loading
-        return abs(current1) > i_max or abs(current2) > i_max
+        return bool(loading.m > self._max_loading)
 
     #
     # Json Mixin interface

roseau/load_flow_single/models/tests/test_lines.py

@@ -138,7 +138,7 @@ def test_res_violated():
     line.max_loading = Q_(50, "%")
     assert line.max_loading.m == 0.5
     assert line.res_violated
-    assert np.allclose(line.res_loading, 10 / (11 * 0.5))
+    assert np.allclose(line.res_loading, 10 / 11)
 
     # Two violations
     lp = LineParameters(id="lp", z_line=1.0, ampacity=9)

roseau/load_flow_single/models/tests/test_transformers.py

@@ -64,12 +64,12 @@ def test_res_violated():
     # Two violations
     transformer.max_loading = 4 / 5
     assert transformer.res_violated is True
-    assert np.allclose(transformer.res_loading, 0.8 * 20 * 3 / 40)
+    assert np.allclose(transformer.res_loading, 0.8 * 20 * 3 / 50)
 
     # Primary side violation
     transformer.max_loading = Q_(45, "%")
     assert transformer.res_violated is True
-    assert np.allclose(transformer.res_loading, 0.8 * 20 * 3 / (50 * 0.45))
+    assert np.allclose(transformer.res_loading, 0.8 * 20 * 3 / 50)
 
     # Secondary side violation
     transformer.max_loading = 1

roseau/load_flow_single/models/transformers.py

@@ -170,28 +170,18 @@ def res_power_losses(self) -> Q_[complex]:
         return power1 + power2
 
     @property
-    def res_loading(self) -> Q_[float] | None:
+    @ureg_wraps("", (None,))
+    def res_loading(self) -> Q_[float]:
         """Get the loading of the transformer (unitless)."""
         sn = self._parameters._sn
-        if sn is None:
-            return None
         power1, power2 = self._res_powers_getter(warning=True)
-        s_max = sn * self._max_loading
-        return Q_(max(abs(power1), abs(power2)) / s_max, "")
+        return max(abs(power1), abs(power2)) / sn
 
     @property
-    def res_violated(self) -> bool | None:
-        """Whether the transformer power exceeds the maximum power (loading > max_loading).
-
-        Returns ``None`` if the maximum power is not set.
-        """
-        sn = self._parameters._sn
-        if sn is None:
-            return None
-        power1, power2 = self._res_powers_getter(warning=True)
-        s_max = sn * self._max_loading
+    def res_violated(self) -> bool:
+        """Whether the transformer power loading exceeds its maximal loading."""
         # True if either the primary or secondary is overloaded
-        return abs(power1) > s_max or abs(power2) > s_max
+        return bool(self.res_loading.m > self._max_loading)
 
     #
     # Json Mixin interface

roseau/load_flow_single/network.py

@@ -681,8 +681,7 @@ def res_lines(self) -> pd.DataFrame:
                 loading = None
                 violated = None
             else:
-                i_max = ampacity * max_loading
-                loading = max(abs(current1), abs(current2)) / i_max
+                loading = max(abs(current1), abs(current2)) / ampacity
                 violated = loading > max_loading
             res_dict["line_id"].append(line.id)
             res_dict["current1"].append(current1)
@@ -739,13 +738,8 @@ def res_transformers(self) -> pd.DataFrame:
             power2 = potential2 * current2.conjugate() * 3.0
             sn = transformer.parameters._sn
             max_loading = transformer._max_loading
-            if sn is None:
-                violated = None
-                loading = None
-            else:
-                s_max = sn * max_loading
-                loading = max(abs(power1), abs(power2)) / s_max
-                violated = loading > max_loading
+            loading = max(abs(power1), abs(power2)) / sn
+            violated = loading > max_loading
             res_dict["transformer_id"].append(transformer.id)
             res_dict["current1"].append(current1)
             res_dict["current2"].append(current2)