Fix examples and missed renamings of P to p

Author: Birgit Schachler

windpowerlib/power_output.py

@@ -112,7 +112,7 @@ def cp_curve_density_corr(v_wind, rho_hub, d_rotor, cp_values):
     p_values = (1 / 8 * 1.225 * d_rotor ** 2 * np.pi *
                 np.power(cp_values.index, 3) * cp_values.cp)
     p_values = pd.DataFrame(data=np.array(p_values), index=cp_values.index,
-                            columns=['P'])
+                            columns=['p'])
     return p_curve_density_corr(v_wind, rho_hub, p_values)
 
 
@@ -144,7 +144,7 @@ def p_curve(p_values, v_wind):
     wind speed given in the power curve is zero.
 
     """
-    power_output = np.interp(v_wind, p_values.index, p_values.P,
+    power_output = np.interp(v_wind, p_values.index, p_values.p,
                              left=0, right=0)
     # Set index for time series
     try:

windpowerlib/tests/modelchain_tests.py

@@ -29,7 +29,7 @@ def setUpClass(self):
         self.test_turbine = {'hub_height': 100,
                              'd_rotor': 80,
                              'turbine_name': 'ENERCON E 126 7500',
-                             'fetch_curve': 'P'}
+                             'fetch_curve': 'p'}
         self.test_wt = wt.WindTurbine(**self.test_turbine)
         self.test_modelchain = {'wind_model': 'hellman',
                                 'rho_model': 'barometric',

windpowerlib/tests/power_output_tests.py

@@ -15,7 +15,7 @@ def setUpClass(self):
         self.d_rotor = 80
         self.cp_values = pd.DataFrame(data={'cp': [0.3, 0.4, 0.5]},
                                       index=[4.0, 5.0, 6.0])
-        self.p_values = pd.DataFrame(data={'P': [300, 400, 500]},
+        self.p_values = pd.DataFrame(data={'p': [300, 400, 500]},
                                      index=[4.0, 5.0, 6.0])
 
     def test_cp_curve(self):