Experimental Investigation of the Impact of Partial Shading Size on Power Losses in Outdoor Solar Modules: Insights from Five Case Studies

Partial shading significantly affects the performance of photovoltaic (PV) systems, resulting in significant power losses and decreased efficiency. This study examines the effect of partial shading on the output power and electrical parameters of photovoltaic modules through field case studies and outdoor experimental tests. Additionally, an I-V tracer, PROVA 1011, was used to experimentally examine 10W and 20W polycrystalline panels under controlled partial shade sizes of 20%, 40%, 50%, 60%, and 80%. The results show that the voltage remains stable at lower shading levels but drops sharply beyond 50%. The current declines linearly with increasing shading, and the power losses reach 88.4% under 80% shading. Five case studies have been considered in this study to analyze rooftop-based partial shading size and the loss calculated using the experimental data. The study shows that power losses vary from 83.87 % to 87.91% due to the partial shading size of 40% to 60% for a 100W module. These findings emphasize the critical impact of rooftop obstacle-based partial shading on PV system losses and the need for practical design of PV installation to mitigate the shading.