The Effect of Shading on the Performance of Photovoltaic Panels

In photovoltaic systems that generate electricity from solar energy, shading can be cast on the panel from sources such as passing clouds or tress. This investigation aims to determine the effect of shading on the performance of PV panels. Analysis was conducted using a poly-crystalline panel, where full and partial shading was applied across the short edge (horizontal shading), long edge (vertical shading) and diagonally across the panel. With the irradiance and temperature of the panel kept constant at 600W/m² and 25°C respectively, it was noticed that the most drastic power loss was due to vertical shading where the power dropped by 95% when only 10% of the panel was fully covered as compared to 30% for the horizontal case, and around 15% for the diagonal case. The impact of bypass diodes on power output was investigated where it was observed that power improvements were more significant for partial than full shading and for partial horizontal, vertical and diagonal shading, power output improved by 20, 10 and 10% respectively.