Merge pull request #39 from opusonesolutions/multi-conductor

Multi-conductor cable radius means outside radius

Author: AnjoMan

carsons/carsons.py

@@ -291,18 +291,15 @@ def GMR_cn(self, phase) -> float:
 class MultiConductorCarsonsEquations(ModifiedCarsonsEquations):
     def __init__(self, model):
         super().__init__(model)
-        self.radius: Dict[str, float] = model.radius
-        self.insulation_thickness: Dict[str, float] = \
-            model.insulation_thickness
+        self.outside_radius: Dict[str, float] = model.outside_radius
 
     def compute_d(self, i, j) -> float:
         # Assumptions:
         # 1. All conductors in the cable are touching each other and
         #    therefore equidistant.
         # 2. In case of quadruplex cables, the space between conductors
         #    which are diagonally positioned is neglected.
-        return (self.radius[i] + self.radius[j]
-                + self.insulation_thickness[i] + self.insulation_thickness[j])
+        return self.outside_radius[i] + self.outside_radius[j]
 
     @property
     def conductors(self):

tests/helpers.py

@@ -95,15 +95,13 @@ def __init__(self, conductors, is_secondary=False):
         self._resistance = {}
         self._geometric_mean_radius = {}
         self._wire_positions = {}
-        self._radius = {}
-        self._insulation_thickness = {}
+        self._outside_radius = {}
 
         for phase, val in conductors.items():
             self._resistance[phase] = val['resistance']
             self._geometric_mean_radius[phase] = val['gmr']
             self._wire_positions[phase] = val['wire_positions']
-            self._radius[phase] = val['radius']
-            self._insulation_thickness[phase] = val['insulation_thickness']
+            self._outside_radius[phase] = val['outside_radius']
 
         self._phases = sorted(list(conductors.keys()))
 
@@ -124,9 +122,5 @@ def phases(self):
         return self._phases
 
     @property
-    def radius(self):
-        return self._radius
-
-    @property
-    def insulation_thickness(self):
-        return self._insulation_thickness
+    def outside_radius(self):
+        return self._outside_radius

tests/test_multi_conductor.py

@@ -21,12 +21,13 @@ def test_triplex_phased_cable():
     Test against 3/0 triplex NS75 aluminum conductor cable.
     """
     phases = 'ABC'
+    insulation_thickness = 0.00137   # meters
     phase_conductor = {
         'resistance': (0.611 * (ohms / miles)).to('ohm / meters').magnitude,
         'gmr': (0.014 * feet).to('meters').magnitude,
         'wire_positions': (0, 5),
-        'radius': (0.464 / 2 * inches).to('meters').magnitude,
-        'insulation_thickness': 0.00137,
+        'outside_radius': ((0.464 / 2 * inches).to('meters').magnitude +
+                           insulation_thickness),
     }
     multi_line_model = MultiLineModel({ph: phase_conductor for ph in phases})
     carsons_model = MultiConductorCarsonsEquations(multi_line_model)
@@ -51,13 +52,17 @@ def test_triplex_secondary():
         'resistance': (0.97 * (ohms / miles)).to('ohm / meters').magnitude,
         'gmr': (0.0111 * feet).to('meters').magnitude,
         'wire_positions': (0, 1),
-        'radius': (0.368 / 2 * inches).to('meters').magnitude,
     }
+    insulation_thickness = 0.08   # inches
     phase_conductor = {
         **conductor,
-        'insulation_thickness': (0.08 * inches).to('meters').magnitude
+        'outside_radius': ((0.368 / 2 + insulation_thickness) * inches
+                           ).to('meters').magnitude,
+    }
+    neutral_conductor = {
+        **conductor,
+        'outside_radius': (0.368 / 2 * inches).to('meters').magnitude,
     }
-    neutral_conductor = {**conductor, 'insulation_thickness': 0}
     multi_line_model = MultiLineModel(
         {'S1': phase_conductor, 'S2': phase_conductor, 'N': neutral_conductor}
     )
@@ -86,26 +91,31 @@ def test_triplex_secondary():
 
 
 @pytest.mark.parametrize(
-    'phases, resistance, gmr, wire_position, radius, insulation_thickness, '
-    'expected_result',
+    'phases, resistance, gmr, wire_position, core_radius,'
+    'insulation_thickness, expected_result',
     [('B', 0.97, 0.0111, (0, 5), 0.368/2, 0.00137, EXPECTED_DUPLEX_IMPEDANCE),
      ('ABC', 0.484, 0.0158, (0, 5), 0.522/2, 0.00137,
       EXPECTED_QUADRUPLEX_IMPEDANCE)]
 )
 def test_multi_conductor_cable_with_neutral(
-        phases, resistance, gmr, wire_position, radius,
+        phases, resistance, gmr, wire_position, core_radius,
         insulation_thickness, expected_result
 ):
     conductor = {
         'resistance': (resistance * (ohms / miles)
                        ).to('ohm / meters').magnitude,
         'gmr': (gmr * feet).to('meters').magnitude,
         'wire_positions': wire_position,
-        'radius': (radius * inches).to('meters').magnitude,
     }
-    phase_conductor = {**conductor,
-                       'insulation_thickness': insulation_thickness}
-    neutral_conductor = {**conductor, 'insulation_thickness': 0}
+    phase_conductor = {
+        **conductor,
+        'outside_radius': ((core_radius * inches).to('meters').magnitude +
+                           insulation_thickness),
+    }
+    neutral_conductor = {
+        **conductor,
+        'outside_radius': (core_radius * inches).to('meters').magnitude,
+    }
 
     line_model_dict = {ph: phase_conductor for ph in phases}
     line_model_dict.update({'N': neutral_conductor})