Partition Definition in 3D Scene with 2-Portrait Trackers

[Alessia]

Dear PVsyst Team,

I’m reaching out to ask for your support regarding a 3D scene I’m simulating using trackers in a 2-portrait configuration.

In this model, I’m defining the partition on two types of trackers:

• One with 2×14 modules, corresponding to a single string.

• Another with 2×28 modules, corresponding to two strings (one on the top row and one on the bottom row of the structure).

I have two main questions:

1. In general, is it necessary to define the partition if the module is already specified as a twin half-cell with 3 submodules in the PAN file? If so, how should the partition be configured?

2. In my specific case, where there is only one string per structure, the partition would logically be 1×1. However, if a partition is still required due to the module’s half-cell architecture (as per question 1), how should I define it in this scenario?

Thanks.

[Michele Oliosi]

Hi !

1. Yes, in general it is necessary to define partitions whenever you want to perform electrical shading calculations using the option "according to module strings". However, if you use the mode "Module layout" then the partitioning is not necessay as the submodule and structure is defined in the PAN file.
2. No, in general the partitioning is not = to 1 string, sometimes you should count several partitions per string. For example, the half-cell parallel structure usually means doubling the number of partitions. You can find various examples here: https://www.pvsyst.com/help/project-design/shadings/electrical-shadings-module-strings/partition-in-strings-of-modules.html. Your cases are the 2TU and 2T respectively.

[Alessia]

Thank you Michele. 

To make sure I fully understand the implications for my specific case:

Since the modules are connected in series (one string per 2x14 structure), shading on the bottom module would affect the performance of the top module as well, even though the top one remains unshaded.

If I simply divide top and bottom modules each into two partitions (totaling 4 vertical submodule partitions per string), I am concerned this may miss the fact that shading on the bottom module electrically impacts the top module through the series string connection.

How would you recommend managing this configuration?

Thanks again.

[Michele Oliosi]

We have calibrated the number of partitions based on the module layout calculation. Therefore, all these effects are taken into account in the partition model. The partition model per se is an approximation that will not always reflect the details of the electrical effect of partial shadings, but that should recover a plausible loss value for a long term (e.g. a year) simulation.

However, for the case of the 2x14 structure, it should not be a partition that traces through the middle of the modules. That would be correct for the case 2T. Instead, this 2x14 structure is in the case 2TU, which has two partitions with size 1x14.