entering 35040 wind_resource data but SAM outputs 8760 generation

Hi Paul,

My goal is to output system generation (or system power) given wind_resource data as input to SAM. I am giving 35040 wind_resource data but the output is 8760 generation. The code is:

ssc = PySSC()
ssc.module_exec_set_print(0)
data = ssc.data_create()
module = ssc.module_create('windpower')

wind_resource = ssc.data_create()

ssc.data_set_number(wind_resource, 'latitude', self.latitude)
ssc.data_set_number(wind_resource, 'longitude', self.longitude)
ssc.data_set_number(wind_resource, 'elevation', self.elevation)
ssc.data_set_number(wind_resource, 'year', self.year)
heights = [self.hub_height_meters, self.hub_height_meters, self.hub_height_meters, self.hub_height_meters]
ssc.data_set_array(wind_resource, 'heights', heights)
fields = [1, 2, 3, 4]
ssc.data_set_array(wind_resource, 'fields', fields)

# temperature_celsius, pressure_atmospheres, wind_meters_per_sec and wind_direction_degrees are all of length 35040

data_matrix = np.matrix([self.temperature_celsius, self.pressure_atmospheres, self.wind_meters_per_sec, self.wind_direction_degrees])
data_matrix = data_matrix.transpose()
ssc.data_set_matrix(wind_resource, 'data', data_matrix.tolist() )

ssc.data_set_table(data, 'wind_resource_data', wind_resource)
ssc.data_set_number(data, 'wind_resource_shear', 0.14000000059604645)
ssc.data_set_number(data, 'wind_resource_turbulence_coeff', 0.10000000149011612)
ssc.data_set_number(data, 'system_capacity', self.system_capacity)
ssc.data_set_number(data, 'wind_resource_model_choice', 0)
ssc.data_set_number(data, 'weibull_reference_height', 50)
ssc.data_set_number(data, 'weibull_k_factor', 2)
ssc.data_set_number(data, 'weibull_wind_speed', 7.25)
ssc.data_set_number(data, 'wind_turbine_rotor_diameter', self.rotor_diameter)
ssc.data_set_array(data, 'wind_turbine_powercurve_windspeeds', self.wind_turbine_speeds)
ssc.data_set_array(data, 'wind_turbine_powercurve_powerout', self.wind_turbine_powercurve);
ssc.data_set_number(data, 'wind_turbine_hub_ht', self.hub_height_meters)
ssc.data_set_number(data, 'wind_turbine_max_cp', 0.44999998807907104)
wind_farm_xCoordinates = [0]
ssc.data_set_array(data, 'wind_farm_xCoordinates', wind_farm_xCoordinates)
wind_farm_yCoordinates = [0]
ssc.data_set_array(data, 'wind_farm_yCoordinates', wind_farm_yCoordinates)
ssc.data_set_number(data, 'wind_farm_losses_percent', 0)
ssc.data_set_number(data, 'wind_farm_wake_model', 0)
ssc.data_set_number(data, 'adjust:constant', 0)

ssc.data_free(wind_resource)
self.ssc = ssc
self.data = data
self.module = module

self.ssc.module_free(self.module)
system_power = self.ssc.data_get_array(self.data, 'gen')

# this system power is 8760. I expect it to be 35040.
Thanks for your time in advance..

Hello,

Are you using the latest version of ssc.dll that comes with SAM 2018.11.11 (Version 200 or 202)? There was a bug in older versions of SSC that caused this problem with subhourly wind data.

You can make a copy of the ssc.dll file from SAM's installation folder and put it in the folder with your Python code.

Best regards,
Paul.