Partition in Pvsyst

[Andel]

Hi PVsyst team,

 

Hopefully I can get support from PVsyst team for my question.

I have layout for solar park that was made in PVcase software. I imported the 3D scene from PVcase into PVsyst. The next step should be "The partition" for electrical shadings calculations. I am a bit confused and I am really not sure if I made the correct partition in PVsyst and I hope to confirm or correct me if the partition that I made is not correct.

I should mention here the tables in the layout are divided into two groups, tables with 2 rows and each row is 24 modules (2 strings, one for upper part and another for the lower part), and tables with 2 rows and each row is 12 modules (1 string for the whole table). See the attached picture that shows the tables shape in PVcase. 

Now when I imported the layout into PVsyst I made the partition as such: for the tables with 2 rows and each row is 24 modules (two strings) I set the value of  Nb.rectangles in height (Y) to be 2 and the value of  Nb.rectangles in length(X) to be 1. See the named picture "Tables of two strings". Then for the tables that with one string I set the value of  Nb.rectangles in height (Y) to be 1 and the value of  Nb.rectangles in length(X) to be 1. See the named picture "Tables of one string".

 

Is that what I did as partition in PVsyst correct?   

I really appreciate any kind help or support from PVsyst team in this regards. This is very important to know because it represent one of our solar parks design . 

 

Thank you in advance. 

 

 

[Michele Oliosi]

Hi,

Please read the following help page: https://www.pvsyst.com/help/shadings_partitioninstrings.htm

It might be correct for the 2*24 table, but it depends on whether the modules have half cut cells in parallel or not. In case of half-cut cell modules, you should make 4 partitions in Y instead of 2.

For the 2*12 table, this is not as resilient to shadings. It's hard to model it with PVsyst, but a good start is:

• standard modules, leave as is NPartY = 1
• half-cut modules, NPartY = 2

[Andel]

I really appreciate your response and thank you for the detailed information.

 

Just I still face some difficulties to understand the partition for the table 2x12, since I am using half cut cell why I don't apply the same technique of the tables 2x24 for the tables 2x12?    

[Michele Oliosi]

Other than what is included in the help, I should say that the partition model is an approximation, that tries to account for mismatch between submodules that are shaded or not. On top of that, in the end the inverter decides which operating point to choose on the total IV curve, which can be quite complex for partial shadings.

In the situation where a string is on two different rows, you will have 1/2 of the modules being affected by shadings most of the time. This causes an increase in mismatch compared to a situation in which modules are all on the same row. This means that this situation is less resilient to shadings. It ensues that there need to be fewer partitions.
 

[Andel]

Thank you so much Michele