We present a methodology for the analysis and the uation of the electrical effects of partial shadings on

a PV array. This methodology is namely developed in a pedagogic tool of the software PVsyst, which aims to explain

how a shaded cell or group of cells behaves within a PV array. We use this tool for understanding the functions of the bypass

diodes, and quantify the array electrical losses in some typical situations, when one or several cells are shaded. We

show that the electrical shading effect is dependent either on the length of the strings, and on the number of strings in

parallel. This method should be applied for accurate shading calculations within the simulation process of PVsyst in a

near future.

Keywords : Shading – Modelling - Simulation-We present a methodology for the analysis and the　uation of the electrical effects of partial shadings on

a PV array. This methodology is namely developed in a pedagogic tool of the software PVsyst, which aims to explain

how a shaded cell or group of cells behaves within a PV array. We use this tool for understanding the functions of the bypass

diodes, and quantify the array electrical losses in some typical situations, when one or several cells are shaded. We

show that the electrical shading effect is dependent either on the length of the strings, and on the number of strings in

parallel. This method should be applied for accurate shading calculations within the simulation process of PVsyst in a

near future.

Keywords : Shading – Modelling - Simulation