Photovoltaic Panel Performance Analysis Under Shading Conditions

The main factor determining the efficiency of the photovoltaic (PV) panel is the solar radiation that is emitted on its surface. It generates electricity through the PV effect and affects the panel temperature, its output current, voltage and power. Very often in the working mode the PV panels, or parts of them are shaded by clouds or nearby objects. Various impurities and deposit materials appear on them. When a cell, or group of cells, is shaded, its resistance increases and its output current decreases. The energy, generated by the other cells, is dissipated by the shaded cell. This causes overheating and further defects. Thus, shading and impurities modify the character of the 1- V curve of the PV panels and reduce their output power. The laboratory equipment of an autonomous PV system, developed in the Department of Electrical Engineering and Physics at “Todor Kableshkov” University of Transport, works in shading conditions. It is realized by PV panel of Longi Solar company, model LR4-72HPH-440M. A simulation and experimental research of the PV panel characteristics under shading conditions is proposed in this paper. The results obtained can be used for teaching in courses related to the application of renewable energy sources.