Anisotropic Diffuse Shading Model for Sun-tracking Photovoltaic Systems

Thiswork ispart of a methodology and set of tools being developed to increase the accuracy of yield predictions for one- and two-axis-tracking photovoltaic plants. The paper presents enhancements incorporated to consider the effects of diffuse irradiance components. Focus resides on the calculation of shading losses based on an anisotropic sky model and considering the effects of the moving 3D tracker arrangement over a complex landscape. Shading factors for two ground-reflected- and three sky-diffuse-irradiance components are calculated individually, on a time-step basis, and for multiple points over the tracker plane. Simulation results are presented for an example two-axis-tracking plant. Effects of geometrical framework, shading of different irradiance components, and simulation detail are discussed. A comparison with state-of-the-art simulation assumptions and practices is performed.