relation: http://eprints.imtlucca.it/2709/ title: A power and energy procedure in operating photovoltaic systems to quantify the losses according to the causes creator: Spertino, F. creator: Ciocia, A. creator: Di Leo, P. creator: Tommasini, R. creator: Berardone, Irene creator: Corrado, Mauro creator: Infuso, Andrea creator: Paggi, Marco subject: Q Science (General) description: Recently, after high feed-in tariffs in Italy, retroactive cuts in the energy payments have generated economic concern about several grid-connected photovoltaic (PV) systems with poor performance. In this paper the proposed procedure suggests some rules for determining the sources of losses and thus minimizing poor performance in the energy production. The on-site field inspection, the identification of the irradiance sensors, as close as possible the PV system, and the assessment of energy production are three preliminary steps which do not require experimental tests. The fourth step is to test the arrays of PV modules on-site. The fifth step is to test only the PV strings or single modules belonging to arrays with poor performance (e.g., I-V mismatch). The sixth step is to use the thermo-graphic camera and the electroluminescence at the PV-module level. The seventh step is to monitor the DC racks of each inverter or the individual inverter, if equipped with only one Maximum Power Point Tracker (MPPT). Experimental results on real PV systems show the effectiveness of this procedure. publisher: Elsevier date: 2015-08-01 type: Article type: PeerReviewed format: application/pdf language: en identifier: http://eprints.imtlucca.it/2709/1/SE-S-15-00766.pdf identifier: Spertino, F. and Ciocia, A. and Di Leo, P. and Tommasini, R. and Berardone, Irene and Corrado, Mauro and Infuso, Andrea and Paggi, Marco A power and energy procedure in operating photovoltaic systems to quantify the losses according to the causes. Solar Energy, 118. pp. 313-326. ISSN 0038-092X (2015) relation: http://www.sciencedirect.com/science/article/pii/S0038092X15002935 relation: 10.1016/j.solener.2015.05.033