Partially shaded operation of a grid-tied PV system

Partial shading of a PV installation has a disproportionate impact on its power production. This paper presents background and experimental results from a single string grid-tied PV system, operated under a variety of shading conditions. In this configuration a shadow can represent a reduction in power over 30 times its physical size. Results are presented relating size and positions of shading to power reduction of the PV system. A simulation method is also described that provides an accurate description of shade based on a single site survey. This process can provide the basis for an accurate simulation of power reduction in a partially shaded PV system.