How is pv-module tolerance incorporated in PV-Syst

[Soldnerkugel]

Module manufacturers always add tolerances to their datasheets, like "300 Wp, 0 to +5W tolerance".

In PV-Syst I can edit this tolerance: "Definition of a PV Module", tab "Basic data".

There's two textboxes: one for entering a minus tolerance, and for entering a plus tolerance. I just entered different values theres but the result in the pv-syst report after simulation is still the same.

How does PV-Syst incorporate these plus and minus tolerances in its simulation?

[André Mermoud]

Thes values are used for the default value of the "Module Quality Loss" parameter.

See our FAQ How to define the "Module Quality Loss" parameter ?

[Soldnerkugel]

but actually changing those values should have an impact on the simulation results?

[André Mermoud]

If in the "detailed losses", page "Module Quality Loss", you have checked "Default", the Module quality loss factor will be reevaluated at the beginning of the simulation as a function of the actual PV module's parameters.

[Soldnerkugel]

Thank you very much, that's exactly what I wanted to know

[Ping]

Hi André Mermoud,

(1) if you check "default", it will usually be -0.8%; actually -0.75% per your definition for the V6 version software, for solar panel with 0~3% tolerance, will get -3%/4 of this factor.

(2) however, most recent solar panel is categorized each 5W, even this case, it says 0~5W tolerance. therefore, I believe, it is better for this case, to have -5W/300W/4=-0.4% for the same reason you have above;

(3) and with Isc current sorting in the installation (within the same category of 5W, solar panel are divided to three current bins by current), we are able to get out the average 2.5W beyond 300Wp, therefore, we would like to use -2.5W/300W=-0.8% as this factor once we do current sorting.

Please let me know your comment.

And actually, I don't understand why you set

"-half of the lower tolerance" in version 5, and

"a quarter of the difference between these values" in version 6.

That's really confusing.

Ping Xi.

 

If in the "detailed losses", page "Module Quality Loss", you have checked "Default", the Module quality loss factor will be reevaluated at the beginning of the simulation as a function of the actual PV module's parameters.

[André Mermoud]

The PV module tolerance is used as default value in a project. You can put here any value. Therefore this value is not of big importance: you can choose it as you like.

See our FAQ How to define the "Module Qualits Loss" parameter?.

At the time of the version 5, most of the modules were specified with -/+ tolerance (usually -/+ 3%). Therefore a loss of half the lower value (1.5%) was pertinent.

Positive sorting appeared more recently on the market. This is the reason why this definition had to be updated.

[aaronrodg]

Good to know about this info. Very useful...