Identifying periods of clear sky direct normal irradiance
Identifying periods of clear sky direct normal irradiance
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DOI：
10.1016/j.renene.2017.06.011
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发表时间：
2017-12-01
期刊：
影响因子：
8.7
通讯作者：
Silva-Perez, M. A.
中科院分区：
文献类型：
--
作者：
Larraneta, M.;Reno, M. J.;Silva-Perez, M. A.
在对直接法线日照(DNI)中的云瞬变效应进行建模时，特别需要确定在观测者和太阳之间没有云的时刻。在这篇文章中，我们提出了一种简单的算法，用于离线检测到观测者的太阳路径不受任何云阻碍的情况。该算法基于测量的天空曲线和晴空曲线之间的关系的表征。晴空识别模块由三个评估和检测指标组成：小时平均值、斜率和线长标准。它们都依赖于根据晴朗天空产生的数据对测量数据进行评估。这三个标准的结合导致了晴天时间的确定。我们通过将我们的结果与最近发表的使用高时间分辨率全球水平辐射(GHI)作为输入的晴空探测算法的结果进行比较来验证我们的算法。当超过50分钟被确定为清晰时，我们获得98%的一致性。(C)2017爱思唯尔有限公司。保留所有权利。
When modeling the effect of the cloud transients in the Direct Normal Insolation (DNI), it is particularly relevant to identify those moments in which there are no clouds between the observer and the sun. In this paper, we present a simple algorithm for offline detection of situations where the sun path to the observer is not obstructed by any cloud. The algorithm is based on the characterization of the relations between the measured and the clear sky curves. The clear sky identification module consists of three evaluation and detection metrics: hourly mean, slope, and line length criterion. All of them rely on the assessment of the measured data against the clear sky generated data. The conjunction of the fulfillment of the three criteria leads to the clear sky hour identification. We validate our algorithm by comparing our results with those obtained from a recently published clear sky detection algorithm that uses high temporal resolution Global Horizontal Irradiation (GHI) as the input. We obtain a 98% agreement when having more than 50 min identified as clear. (C) 2017 Elsevier Ltd. All rights reserved.