rdtools.filtering.pvlib_clearsky_filter

rdtools.filtering.pvlib_clearsky_filter(poa_global_measured, poa_global_clearsky, window_length=90, mean_diff=75, max_diff=75, lower_line_length=-45, upper_line_length=80, var_diff=0.032, slope_dev=75, lookup_parameters=False, **kwargs)

Filtering based on the Reno and Hansen method for clear-sky filtering as implimented in pvlib. Requires a regular time series with uniform time steps.

Parameters:

  • poa_global_measured (pandas.Series) -- Plane of array irradiance based on measurments

  • poa_global_clearsky (pandas.Series) -- Plane of array irradiance based on a clear sky model

  • window_length (int, default 10) -- Length of sliding time window in minutes. Must be greater than 2 periods.

  • mean_diff (float, default 75) -- Threshold value for agreement between mean values of measured and clearsky in each interval, see Eq. 6 in [1]. [W/m2]

  • max_diff (float, default 75) -- Threshold value for agreement between maxima of measured and clearsky values in each interval, see Eq. 7 in [1]. [W/m2]

  • lower_line_length (float, default -5) -- Lower limit of line length criterion from Eq. 8 in [1]. Criterion satisfied when lower_line_length < line length difference < upper_line_length.

  • upper_line_length (float, default 10) -- Upper limit of line length criterion from Eq. 8 in [1].

  • var_diff (float, default 0.005) -- Threshold value in Hz for the agreement between normalized standard deviations of rate of change in irradiance, see Eqs. 9 through 11 in [1].

  • slope_dev (float, default 8) -- Threshold value for agreement between the largest magnitude of change in successive values, see Eqs. 12 through 14 in [1].

  • lookup_parameters (bool, default False) -- Look up the recomended parameters [2] based on the frequency of poa_global_measured. If poa_global_measured has a defined frequency, this overrides the values of window_length, max_diff, var_diff, and slope_dev. For frequencies below 1 minute or greater than 30, the lookup uses the recomended parameters for 1 or 30 minutes respectively. If poa_global_measured doesn't have a defined frequency, the passed or default values of the parameters are used.

  • kwargs -- Additional arguments passed to pvlib.clearsky.detect_clearsky return_components is set to False and not passed.

Returns:

Boolean Series of whether or not the given time is clear.

Return type:

pandas.Series

References

[1] M.J. Reno and C.W. Hansen, Renewable Energy 90, pp. 520-531 (2016) [2] D.C. Jordan and C.W. Hansen, Renewable Energy 209 pp. 393-400 (2023)