Convert str to numeric in TurbineClusterModelChain incl. test

tests/test_turbine_cluster_modelchain.py

@@ -272,3 +272,21 @@ def test_tc_modelchain_with_power_curve_as_dict(self):
             power_plant=wtc.WindTurbineCluster(**my_cluster))
         test_tc_mc.run_model(self.weather_df)
         assert_series_equal(test_tc_mc.power_output, power_output_exp)
+
+    def test_heigths_as_string(self):
+        """Test run_model if data heights are of type string."""
+
+        # Convert data heights to str
+        string_weather = self.weather_df.copy()
+        string_weather.columns = pd.MultiIndex.from_arrays([
+            string_weather.columns.get_level_values(0),
+            string_weather.columns.get_level_values(1).astype(str)])
+
+        # Heights in the original DataFrame are of type np.int64
+        assert isinstance(self.weather_df.columns.get_level_values(1)[0],
+                          np.int64)
+        assert isinstance(string_weather.columns.get_level_values(1)[0], str)
+
+        test_mc = tc_mc.TurbineClusterModelChain(
+            power_plant=wtc.WindTurbineCluster(**self.test_cluster))
+        test_mc.run_model(string_weather)

windpowerlib/turbine_cluster_modelchain.py

@@ -8,6 +8,7 @@
 SPDX-License-Identifier: MIT
 """
 import logging
+import pandas as pd
 from windpowerlib import wake_losses
 from windpowerlib.modelchain import ModelChain
 
@@ -266,6 +267,10 @@ def run_model(self, weather_df):
         'wind_speed'
 
         """
+        # Convert data heights to integer. In some case they are strings.
+        weather_df.columns = pd.MultiIndex.from_arrays([
+            weather_df.columns.get_level_values(0),
+            pd.to_numeric(weather_df.columns.get_level_values(1))])
 
         self.assign_power_curve(weather_df)
         self.power_plant.mean_hub_height()