The 443,2 kWp PV generator is composed by 2686 modules with the following characteristics:

o Nominal Power: 165 Wp o Power Tolerance: 5% o Voltage MPP: 17.4 Vdc o Frameless, transparent Tedlar.

Modules were packed in groups of 360 units. 16 ones of each group were randomly chosen and sent to IER-CIEMAT for independent quality control and power measuring. Previously, 4 modules were calibrated and used as reference ones for the whole campaign of tests both in IER-CIEMAT and in ISOFOTON factory. IER-CIEMAT2 is an Spanish public laboratory devoted to investigation and certification in the field of renewable energies, including PV.

Due to voltage input of inverter, a configuration of 79 rows with 34 modules in series has been used. Since dispersion losses are directly related to number of modules in series, it is recommended to classify them by current values when that number is high.3

In order to carry out classification previously to manufacturing, an internal production database was used as reference. Therefore three categories were established so modules were classified as soon as power was measured. It should be noted that both values from database and power measuring were corrected to include reference from CIEMAT.

PV generator is electrically DC floating. Due to high voltages used (600 Vdc), a permanent insulation monitoring device is installed inside DC protection and control box. Several mechanisms of protection can be activated when an insulation fault is detected: for example, disconnection of PV generator and inverter, short-circuit of PV generator and direct connection to earth4. This action can be programmed and selected through remote control.