"Electrical behaviour of PV arrays" graphic toll bug

[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

[André Mermoud]

On this graph, the resulting I/V curve (String#2, 2 unshaded sub-modules) is not drawn.

This is indeed a bug.

Except this problem, the graph seems correct.