Power output of a pv module strongly depends on the irradiance it receives. There are many factors which limit this irradiance and badly effect power output of solar PV module. The most prominent are soiling and shading due to surrounding environment. The most damaging one is the exposure of different cells to different irradiances which is called partial shading. The subject of partial shedding and its effects on Photo Voltaic (PV) system are receiving much attention of researchers. In order to model PV system in such conditions, and design a PV system that is immune and tolerant to the problem being addressed, several research articles have been reviewed in this study. Different techniques have been summarized and briefly described here, giving an insight to model PV system and mitigate the problem, with different tested configurations that are more effective in such conditions.