Fix per uniting of lines with not same nominal voltage at both side (#…

…651)

* Fix per uniting of lines with not same nominal voltage at both side

Signed-off-by: Geoffroy Jamgotchian <geoffroy.jamgotchian@rte-france.com>

pypowsybl/network/impl/perunit.py

@@ -77,11 +77,25 @@ def _per_unit_r(self, df: pd.DataFrame, columns: List[str], nominal_v: pd.Series
         for col in columns:
             df[col] /= factor
 
+    def _per_unit_r_not_same_nom_v(self, df: pd.DataFrame, columns: List[str], nominal_v1: pd.Series, nominal_v2: pd.Series) -> None:
+        factor = nominal_v1 * nominal_v2 / self.sn
+        for col in columns:
+            df[col] /= factor
+
     def _per_unit_g(self, df: pd.DataFrame, columns: List[str], nominal_v: pd.Series) -> None:
         factor = nominal_v ** 2 / self.sn
         for col in columns:
             df[col] *= factor
 
+    def _y(self, df: pd.DataFrame, r_col: str, x_col: str) -> pd.Series:
+        return pd.Series(df.apply(lambda row: np.reciprocal(np.complex128(row[r_col] + row[x_col] * 1j)), axis=1))
+
+    def _per_unit_g_not_same_nom_v(self, df: pd.DataFrame, column: str, ytr: pd.Series, nominal_v1: pd.Series, nominal_v2: pd.Series) -> None:
+        df[column] = (df[column] * nominal_v1 * nominal_v1 + (nominal_v1 - nominal_v2) * nominal_v1 * ytr.apply(lambda row: row.real)) / self.sn
+
+    def _per_unit_b_not_same_nom_v(self, df: pd.DataFrame, column: str, ytr: pd.Series, nominal_v1: pd.Series, nominal_v2: pd.Series) -> None:
+        df[column] = (df[column] * nominal_v1 * nominal_v1 + (nominal_v1 - nominal_v2) * nominal_v1 * ytr.apply(lambda row: row.imag)) / self.sn
+
     def _per_unit_i(self, df: pd.DataFrame, columns: List[str], nominal_v: pd.Series) -> None:
         factor = self.sn * 10 ** 3 / (self.sqrt3 * nominal_v)
         for col in columns:
@@ -163,11 +177,17 @@ def get_lines(self) -> pd.DataFrame:
             a per-united dataframe of lines.
         """
         lines = self._network.get_lines()
-        nominal_v = self._get_indexed_nominal_v(lines, 'voltage_level2_id')
+        nominal_v1 = self._get_indexed_nominal_v(lines, 'voltage_level1_id')
+        nominal_v2 = self._get_indexed_nominal_v(lines, 'voltage_level2_id')
         self._per_unit_p(lines, ['p1', 'p2', 'q1', 'q2'])
-        self._per_unit_i(lines, ['i1', 'i2'], nominal_v)
-        self._per_unit_r(lines, ['r', 'x'], nominal_v)
-        self._per_unit_g(lines, ['g1', 'g2', 'b1', 'b2'], nominal_v)
+        self._per_unit_i(lines, ['i1'], nominal_v1)
+        self._per_unit_i(lines, ['i2'], nominal_v2)
+        ytr = self._y(lines, 'r', 'x')
+        self._per_unit_r_not_same_nom_v(lines, ['r', 'x'], nominal_v1, nominal_v2)
+        self._per_unit_g_not_same_nom_v(lines, 'g1', ytr, nominal_v1, nominal_v2)
+        self._per_unit_g_not_same_nom_v(lines, 'g2', ytr, nominal_v2, nominal_v1)
+        self._per_unit_b_not_same_nom_v(lines, 'b1', ytr, nominal_v1, nominal_v2)
+        self._per_unit_b_not_same_nom_v(lines, 'b2', ytr, nominal_v2, nominal_v1)
         return lines
 
     def get_2_windings_transformers(self) -> pd.DataFrame:

tests/test_per_unit.py

@@ -9,6 +9,7 @@
 import pandas as pd
 from numpy import NaN
 import util
+import pytest
 
 
 def test_bus_per_unit():
@@ -413,3 +414,14 @@ def test_ratio_tap_changers_per_unit():
                                      'alpha'],
                             data=[[1, 0, 2, 3, True, True, 158.0, 0.0, 'VLLOAD_0', 1.00, NaN]])
     pd.testing.assert_frame_equal(expected, n.get_ratio_tap_changers(), check_dtype=False, atol=1e-2)
+
+def test_lines_not_same_nominal_voltage_per_unit():
+    n = pp.network.create_ieee14()
+    n = per_unit_view(n, 100)
+    lines = n.get_lines()
+    assert lines.loc['L7-8-1']['r'] == 0
+    assert lines.loc['L7-8-1']['x'] == pytest.approx(0.17615, rel=1e-5)
+    assert lines.loc['L7-8-1']['g1'] == pytest.approx(0, rel=1e-16)
+    assert lines.loc['L7-8-1']['g2'] == pytest.approx(0, rel=1e-16)
+    assert lines.loc['L7-8-1']['b1'] == pytest.approx(0, rel=1e-16)
+    assert lines.loc['L7-8-1']['b2'] == pytest.approx(0, rel=1e-16)