Since frameless modules are used, secondary support structure was designed in order to withstand with winds levels required by normative. Besides an special adhesive replaced metallic contacts between parts of structure of different metallic compounds. These two facts and the height of the main structure motivated a test of a prototype according to standard E 1830-01 "Standard Test Methods for Determining Mechanical Integrity of Photovoltaic Modules”, chapter 5.5 "Cyclic Load Test Apparatus” and chapter 5.5.1 "Air Bag Scheme”. The aim of this test was to check if the set of structure and frameless module could deal with:

o A static load test to 2400 Pa to simulate wind loads on both module surfaces corresponding to a wind speed of 58 m/s (209 km/h). This test was satisfactorily fulfilled after 100 cycles of 2400 Pa static load. o A cyclic load test of 10 000 cycles duration and peak loading to 1440 Pa to simulate dynamic wind. This test was satisfactorily fulfilled.

Final result of the test can be observed in next photograph. After 87 cycles of 3200 Pa static load (278 km/h), part of the secondary structure was broken and then the module too. Before these 87 cycles, three sets of 100 cycles with 2400, 2800 and 3000 Pa were applied successfully.

II. Inverter

The consortium decided to choose the inverter equipment through a call for tender. Three important European manufacturer were invited to participate. Finally the ACEF model from Enertron was selected. This model has next characteristics: o Self commuted with IGBT o AC Current by hysteresis bands. o Nominal Power: 125 kW (three units) o Input: 450 — 756 Vdc (MPP: 450 — 620 Vdc) o THD (Current, 100% load) < 5% o Power Factor: >98% for output above 25% o Maximum Efficiency (including LF transformer): 96% o European Efficiency (including LF transformer): 94% o Noise level: <65 dB.

Three main features must be highlighted:

o A Master-Slave-Slave control technology is used. Global efficiency will be improved, especially during morning and afternoon and with low irradiance levels. Control equipment is independent from inverters, so any of them can be selected as Master or Slave.

o An additional inverter will be installed in parallel as stand-by. This way availability of energy can be improved providing a fast response when an inverter is damaged. o As a condition included in the contract, values of efficiency and availability of equipments are guaranteed by the manufacturer. Penalty can be applied in case of deviation.