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[Kamil Jeznach]

Hi. Is it possible to calculate shading losses for whole string of modules? I'll give you example:

- 10 modules, 9 of them no shading 0%, 1 of them has 99.7% (1 modul is under additional roof):

- I would expect 100% losses due to 1 string connection. The thing is that simulation calculates it as only 10% loss! In reality I'll have 0 kWh, on the simulation results I have 2500 kWh. 

Any idea how to force PV Syst to calculate string shading insted of one module shading?

[developer_mh]

Hi Kamil,

I think the problem here is that the one module under the roof which has 100% direct shading perhaps isn't considered correctly regarding the diffuse shading, which should also be 100%. Could you send me the project file?

But in general, what happens if you have a string connection like the above is that all modules are forced down to the i v curve from the diffuse irradiance, which is not 0. This is why you don't get 0 kWh output. All bypass diodes of the shaded module would be active so that you loose a bit additional energy (current from the other modules * diode voltage), but you'll still get energy out of the string.

You can also have a look here:

https://help.valentin-software.com/pvsol/2018/calculation/pv-field/

Hope that helps, kind regards.

Martin