Shadow shielding identification method and device for photovoltaic string

Abstract

The invention provides a shadow shielding identification method and device for a photovoltaic string. The method comprises the following steps: obtaining the direct current power of each photovoltaicstring corresponding to a target inverter in an effective acquisition period at each acquisition moment; performing data standardization processing on the direct current power of each photovoltaic string at each acquisition moment to obtain the power generation efficiency of each photovoltaic string at each acquisition moment; respectively calculating power generation efficiency discrete rates ofall the photovoltaic strings at each acquisition moment; at each acquisition moment, clustering the power generation efficiency of all the photovoltaic strings to obtain two clustering clusters, and calculating a relative error between central values of the two clustering clusters; and at each acquisition moment, when the power generation efficiency dispersion rate is greater than a dispersion rate threshold value and the relative error is greater than an error threshold value, judging that the photovoltaic string in the clustering cluster with the smaller central value has shadow shielding atthe acquisition moment. According to the invention, accurate identification of shadow shielding of the photovoltaic string is realized on the basis of not needing meteorological data.

Description

technical field [0001] The present invention relates to the technical field of photovoltaic power generation, and more specifically, to a method and device for identifying shadows of photovoltaic strings. Background technique [0002] Photovoltaic power generation has been widely concerned and promoted in recent years due to its clean and efficient advantages, and the environment of photovoltaic power generation has become increasingly diverse, such as mountains, deserts, Gobi, and rooftops. If installed improperly, mountains, columns, foreign objects or growing vegetation in the surrounding environment of photovoltaic modules will cause shadows to block photovoltaic modules. Shadow shading will cause the power generation curve of photovoltaic modules to show multi-peaks, making it impossible to track the maximum power point, which will affect the efficiency of photovoltaic power generation; long-term fixed area shading will form a hot spot effect, increasing the risk of agi...

AI Technical Summary

Problems solved by technology

However, many photovoltaic power generation scenarios in practical applications, such as small and medium-sized power stations such as civil or industrial and commercial roofs, are not equipped with environmental sensors, and meteorological data cannot be obtained, and photovoltaic power stations such as mountain power stations with large differences in the installation environment of photovoltaic modules are collected by environmental sensors. Meteorological data cannot represent component irradiation at different inclinations and azimuths

Therefore, the current methods for identifying shadow occlusions have limitations in photovoltaic power generation scenarios, and cannot accurately identify shadow occlusions in all photovoltaic power generation scenarios

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