**5. Conclusions**

**Figure 9.** PV faults and defects in the 108 kWp PV plant: (a) snail tracks (b) hot spots and burn marks.

106 Solar Panels and Photovoltaic Materials

**Figure 10.** Electrical parameter distributions: (a) STC peak power, (b) STC fill factor (c) max. power voltage, (d) max. power current, (e) open circuit voltage, (f) short circuit current, (g) serial resistance, (h) parallel resistance (9 kWp PV plant).

The GIS tool presented here has shown itself to be of great use when analyzing degradation effects on a PV field, the location of the most common PV defects, and their overall correlation with the plant. Although useful information was found in both case studies, the application of GIS to large plants seems to be more viable than for small installations.

The GIS tool is extremely useful for supervising the degradation of electrical parameters in a power plant and the evolution and distribution of defects in a PV field. Researchers and maintainers are encouraged to use it on their installations and compare results. We will continue to add periodical measurements and inspections to the geo-database and the real degradation effects of the PV field will then be completely analyzed. Such analysis will lead to more economical and effective maintenance and replacement strategies.

A systematic organization and analysis of measurements thanks to the implementation of GIS applications not only allows preliminary preventive maintenance actions to be carried out, such as replacing damaged PV modules, redistributing PV modules according to their performance, and developing specific supervision, cleaning, and maintenance procedures for modules affected by PV faults, but also makes feasible the supervision of the degradation of electrical parameters in the power plant and the evolution and distribution of defects in the PV field.
