Effect of the by-pass diodes with half cell modules

[MarcosdelBlanco]

Good morning,

I have been reading quite a lot of literature about this, and maybe that is the reason why I am still a but confused about this topic. I will mention two sources that I have consulted for this topic.

https://www.pvsyst.com/help/modulelayout_bypasseffect.htm

https://www.recgroup.com/sites/default/files/documents/whitepaper_twinpeak_shading_properties_eng.pdf

My scenarios:

1) Structure with 4 modules in landscape configuration, half cells, connected to string inverter with 2 strings per MPPT. When we define the strings in width in PVsyst, should we define 6? As we have two strings, but every string is divided in three submodules, would make sense to me. Some sources state up to 12 strings in width, as every module have 3 by pass diodes.

2) Same scenario, but 2 modules in portrait. Strings in width=4?

Lastly, to confirm, if we have a central inverter, no matter the by-pass diodes neither the configuration (4 landscape/2 portrait), that we should define 2 strings in width, right?

Thanks for your help, really appreciated.

Marcos

[dtarin]

What is your string size?

With half-cell modules, in landscape orientation, you would not see any benefit from the bypass modules, as both halves will be shaded during row-row shading conditions, across the length of the row/string.

In portrait orientation, with regular row-row shading, you could see some benefit, and if you have 2 in portrait, you would define 4 strings in height. If there is considerable shading from trees or buildings, this would not likely be the case, and you would model strings in their full size.