Qualification of arcing risks in PV modules

The work presented was carried out within a current German research project at TÜV Rheinland in Germany together with the Fraunhofer Institute ISE and the Fire Department of Munich, which examines fire risks and determines enhanced safety measures for PV systems. In principle, contact defects (due to production faults or thermo-mechanical fatigue) in the DC circuit of a module can be named as potential sources of arcs during the operating lifetime. This work reflects general strategies for qualifying risks at cell connectors in general and transfers them to arcing risks in PV modules. To generate technical data, 20 crystalline PV modules with soldering defects were exposed to different test sequences to reproduce similar faults such as focal overheating or even electric arcs. On this basis, combinations of dynamic mechanical or thermo-mechanical loads were applied with a forward bias to induce stressing on the current-carrying parts and connector joints in a module. The derivation of a potentially useful test method is given and production-oriented quality monitoring measures are proposed.