Clear-Sky Detection Using Time-Averaged, Tilted-Plane Data

Clifford Hansen, Dirk Jordan

Research output: Contribution to conferencePaper


A method is presented to detect clear-sky periods for plane-of-array, time-averaged irradiance data that is based on the algorithm originally described by Reno and Hansen. We show this new method improves the state-of-the-art by providing accurate detection at longer data intervals, and by detecting clear periods in plane-of-array data, which is novel. We illustrate how accurate determination of clear-sky conditions helps to eliminate data noise and bias in the assessment of long-term performance of PV plants.
Original languageAmerican English
Number of pages4
StatePublished - 2023
Event2023 IEEE 50th Photovoltaic Specialists Conference (PVSC) - San Juan, Puerto Rico
Duration: 11 Jun 202316 Jun 2023


Conference2023 IEEE 50th Photovoltaic Specialists Conference (PVSC)
CitySan Juan, Puerto Rico

NREL Publication Number

  • NREL/CP-5K00-88843


  • clear-sky conditions
  • default parameters
  • detection conditions
  • false negative
  • false positive
  • mixed state
  • photovoltaic system
  • sky conditions
  • time series


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