METIO question

[Andre]

Hi,

According to the PVsyst model, the highest value of the voltage of an open circuit of a PV module is -10 C. When I select a temperature, for example, -20 C, this is the voltage of a lover than at -10C. In accordance with the technological tools of manufacturers of inverters (SMA or ABB), this voltage continues to increase at a lower temperature.

I design PV systems in Ukraine, where winter temperatures can drop to -20 C.

I'm confused. What data do I need to use when determining the number of modules in a row? :ugeek:

[André Mermoud]

There is indeed a little limitation/error in the model of PVsyst.

When the diode Saturation current goes below 0.02 pA, it is limited to this very low value, for numerical reasons in the model calculation.

This may arise with modules of high serie resistance (close to the RSerei limit), i.e. low diode ideality factors (<0.95). It appears with very low temperatures (< -10°C).

This inverses the muVoc coefficient below a limit temperature, ,but has a very low effect on the model results.