Simulation with incoherent results

[Manuelsl]

Dear Sir

I have performed the simulation of a grid connected PV plant that consist on 6 sub-arrays.

Each sub-array has the same inverters, shading scene, numbers of modules and strings and detailed losses, ..

Version A is formed by 1 array with 370 Wp modules and 5 arrays with 365 modules.

Version B is formed by 2 arrays with 370 modules and 4 arrays with 365 modules.

When carrying out the simulation, option B should give production and PR higher than variant A because that configuration has more peak power but it is just the opposite.

I have check module performance at .pan files and the values are ok.

I work with 6.75 PVsyst version.

Could you give me an explanation?

Thanks

[André Mermoud]

In your comparison, the second option certainly gives a higher yield (E_Grid). Please check.

However if you have identical PV model behaviors, the PR should be identical, as you have different Nominal powers, compensated by different efficiencies.

Except if you have overload losses. In this case, you will have higher overload losses with the second option, and therefore lower PR.

NB: Please remember that the PR doesn't depend on the Efficiency. A higher efficiency means a lower area for the same nominal STC power, and therefore a lower Gincid.

This result may be biased:

- If the low-light performance of both modules is not identical (essentially depending on Rserie)

- If the PNom of both modules (370 and 365) are not rigourously equal to the Imp * Vmp product at STC.

Please see the FAQ Why is the Pmpp of my module different of the specified value ?