handle case of simulation runs with no wheel power available - ignore calculation of k_vehline

VectoCore/VectoCore/OutputData/ModalDataContainer.cs

@@ -193,6 +193,7 @@ namespace TUGraz.VectoCore.OutputData
 				return _vehLine[fuel.FuelType];
 			}
 
+			if (Data.AsEnumerable().Any(r => r.Field<SI>(ModalResultField.P_wheel_in.GetName()) != null)) {
 				double k, d, r;
 				VectoMath.LeastSquaresFitting(
 					GetValues(
@@ -207,6 +208,9 @@ namespace TUGraz.VectoCore.OutputData
 				return _vehLine[fuel.FuelType];
 			}
 
+			return null;
+		}
+
 		public void CalculateAggregateValues()
 		{
 			var duration = Duration;

VectoCore/VectoCore/OutputData/SummaryDataContainer.cs

@@ -444,7 +444,10 @@ namespace TUGraz.VectoCore.OutputData
 				
 				row[FcCol(Fields.K_ENGLINE, suffix)] = correction.ConvertToGramPerKiloWattHour();
 
-				row[FcCol(Fields.K_VEHLINE, suffix)] = modData.VehicleLineSlope(fuel).ConvertToGramPerKiloWattHour();
+				var vehLine = modData.VehicleLineSlope(fuel);
+				if (vehLine != null) {
+					row[FcCol(Fields.K_VEHLINE, suffix)] = vehLine.ConvertToGramPerKiloWattHour();
+				}
 
 				var fcEssCorr = fcModSum + correction * workESS;
 				row[FcCol(Fields.FCESS_H_CORR, suffix)] = duration != null ? (fcEssCorr / duration).ConvertToGrammPerHour() : null;