Aging losse

[Zahra]

Hello,

I am seeking clarification on the module ageing and mismatch loss parameters in PVsyst.

1. Isc and Voc Dispersion: The model uses "Isc dispersion RMS" and "Voc dispersion RMS" as inputs. Are these values the same as the standard ISC and VOC found on a module's datasheet, or are they different parameters representing manufacturing variations? Where can I typically find these dispersion values for a specific module?

2. Degradation Weighting: The default setting often shows a split (e.g., 80/20) for how degradation is attributed to different loss categories. Could you explain the significance of this weighting and how it influences the simulation results?

3. Mismatch with a Single Module: If my system consists of only a single PV panel, do I still need to model mismatch losses (the one in the ageing tab), and if so, why? What is the technical justification for this in PVsyst's simulation?

4. Types of Mismatch Loss: How does the "mismatch loss" calculated within the ageing model differ from the "mismatch losses" specified in the separate Mismatch tab of the software?

5. Global and Mismatch Factors: How does PVsyst calculate the "Individual PV module: Global degradation factor" and "Mismatch degradation factor" based on the number of simulation years? Is this calculation based on a predefined formula, or is it a result of the Monte Carlo simulation itself?

Thank you for your detailed guidance on these topics.

[André Mermoud]

The answers to your questions are fully explained in the help:

https://www.pvsyst.com/help/project-design/array-and-system-losses/ageing-pv-modules-degradation/index.html?h=ageing

https://www.pvsyst.com/help/project-design/array-and-system-losses/ageing-pv-modules-degradation/module-performance-degradation.html

1. - ISC dispersion has nothing to do with the datasheets information. Its nature is explained in the help.

2. - You can evaluate the effect of the Current and Voltage degradation weighting by yourself, by excuting several simulations. You will see that this is not very significant. 

3. - When you have one only module, it is quite obvious that you don't have any mismatch loss. 

4. - In the ageing process, the mismatch between "degraded" modules increases along the time. 

5. - This is an input parameter. The global degradation is  the sum of the individual PV modules degradation and the increasing mismatch.