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Impact of Dynamic-Mechanical Load on PV Modules Mounted on Single-Axis Tracker
D. Stellbogen, P. Lechner, O. Schanz, S. Hummel, J. Schnepf, M. Kaiser
Tracker, PV Module, microcracks, Field Monitoring
PV Systems - Performance, Applications and Integration
Subtopic: Design and Installation of PV Systems
Event: 35th European Photovoltaic Solar Energy Conference and Exhibition
Session: 6CV.2.5
1909 - 1913
ISBN: 3-936338-50-7
Paper DOI: 10.4229/35thEUPVSEC20182018-6CV.2.5
0,00 EUR
Document(s): paper, poster


PV modules with crystalline silicon technology in some cases exhibit cells with microcracks which provokes concerns about the impact of such microcracks on the energy delivery performance as well as the reliability of the modules. Further, the increasing application of single-axis solar trackers in PV plants raises the question whether this might cause special performance and reliability challenges due to the increased mechanical stress executed onto the modules. In order to access the extend of deflections induced onto the PV modules in such installations and the impact these deflections might have on the power and energy yield, a field investigation has been conducted at the ZSW test site Widderstall with complementary laboratory tests. Two PV modules with initial microcracks were monitored mounted on a single-axis tracker and underwent laboratory pre- and post-characterisation as well as power measurements in artificial deflection. The sample modules showed only a moderate STC power loss after one year of operation, which could not certainly be attributed to the microcracks, and no further power decrease after one and a half years. The module back surface deflections recorded in the field were almost entirely within a few millimeters. In flash simulator measurements with artificial deflection, a significant power reduction was observed only at deflections of 5 mm or more to the back. The combination of these findings with the field observations indicates that energy yield losses induced by deflections from daily cyclic tracker movements and wind load pressure are not expected.