Patent ID: 9112078
Filing Date: 2015-08-18
Classification: F24S,H01L,H02S,Y02E

Abstract:
1. A method of recognizing shadowing events caused by shadow casting obstacles that are essentially opaque, and affecting at least one individual photovoltaic module of a plurality of similar photovoltaic modules, the method comprising: recording the electric power values produced by all individual photovoltaic modules of the plurality of similar photovoltaic modules at multiple positions of the sun over a plurality of days; normalizing the recorded electric power values to a common standard; defining an expected power value of the normalized electric power value produced by each individual photovoltaic module of the plurality of similar photovoltaic modules separately for each of the multiple positions of the sun as a maximum value of the normalized electric power values that are at a present day produced by the individual photovoltaic modules of the plurality of similar photovoltaic modules at the respective position of the sun, wherein the expected value of the electric power comprises an influence of clouds affecting all individual photovoltaic modules of the plurality of similar photovoltaic modules; defining an ideal power course of the electric power produced by each individual photovoltaic module over the present day by fitting a curve to peak values of the electric power values recorded for at least one photovoltaic module of the plurality of similar photovoltaic modules at the same positions of the sun during a plurality of previous days, the curve corresponding to cloud-free sun without shadow casting obstacles; comparing the electric power values produced by each of the individual photovoltaic modules at each of the multiple positions of the sun on the present day with the respective ideal power course and the respective expected value; for all positions of the sun at which the electric power value produced by any individual photovoltaic module falls short of the ideal power course on the present day, defining a shadowing probability for the respective photovoltaic module of not less than zero, a magnitude of the shadowing probability for the respective photovoltaic module increasing with increasing difference between the normalized electric power value produced by the respective photovoltaic module and the expected power value at the respective position of the sun; and using the shadowing probability as a criterion for determining whether or not to remove a shadow casting obstacle and removing the shadow casting obstacle if determined to do so.