atgosat

Hello everybody, Today I read an article by PVsyst where the mismatch losses and I-V curve behaviour under partial shadings where analized, like teh electrical shanding losses. I wanted to try that by myself with the tool PVsyst includes, but I came up to something that I belive is a bug. I use 72 cell modules with 3 bypass diodes. I suppose that a whole submodule (24 cells) is shaded, as when a module is landscape-oriented and is shaded from the bottom. I simulate only 2 modules in parallel, where the 2nd module has the same shadings as the 1st one, and I obtain the following I-V curve: The operation point seems to be floating in the middle graph, not belonging to any curve. I expected that point to be located over the black curve as it accounts both modules (strings), but the Poper point seems to be much higher than the black curve, so I'm not sure exactly what is going on here. I believe that there must be a logical explanation for this and that I must be missing somenthing, can anyone clarify this to me? Thanks in advance, Atanas

Hello everybody, Recently I've encountered a problem regarding the shading diagram and I haven't been able to come up with a logical explanation. When I perform the shadings animation of my plant for the 21st of December, I obtain the following shadings curve: As per design criteria, there are no shadings between 10 and 14 h. However, when I compute the shading factor tables and display the graph, I obtain the following: If I observe the 1% shading loss curve, it turns out that it cuts the sun path curve for the 22nd of December during midday. This shocks me a little bit as when I perform the shadings animations there are no shadings at all, but according the shading factor diagram, shadows appear at midday out of nowhere, and I am not able to understand this behaviour. Has anyone else experienced this kind of behaviour, or does anybody know what can it be due to? Thanks in advance for the help, Atanas