Experimental Analysis of Electrical and Thermal Effects of Various Configurations of Partial Shading on Three Different Solar Module Technologies

Photovoltaic (PV) cells can be damaged by reverse bias stress if it is partially shaded. The large number of cells in the module can provide the driving force for reverse breakdown to occur and this can in turn lead to high temperature, high current density and high-packaging materials as well lower the performance of solar modules. Due to partial or complete shading of the cells of photovoltaic system, the power generation is generally affected. By partial shading the module, bypass diodes present in the photovoltaic system prevent the high reverse voltage across the shaded cells. When the current discrepancy is identified the bypass diodes gets ON. Such variations are identified between the strings of cells inside the module, which occurs due to partial shading. If the cell is shaded or not in a proper working condition, instead of generating it start consuming power from the abutting series of solar cells. In big areas where thousands of solar panels are installed, electrical testing at each individual PV panel is difficult and time consuming.In this paper, a method of thermal imaging is used to expedite the identification of inoperative PV cells. The experimental analysis is performed by considering the bypass diodes in all three technologies namely mono-crystalline, multi-crystalline and hetero-junction with intrinsic type solar cell. Various configurations of partial shading are considered to analyze the electrical and thermal effect on solar module.