Advances in the location and repairing of ribbon interruptions in photovoltaic modules

Abstract

One of the most frequent failures in PV modules is the total or partial interruption of ribbons that connect the cells in the module. In the case of modules with cells that have two ribbons on their surface, it is possible to distinguish between single interruptions (affecting only one ribbon of a cell) and twin interruptions (affecting both ribbons of a cell). In the case of repairing twin interruptions, it is possible to restore a significant part of the expected power, according to the nominal values of the module, which in modules with three diodes is in the order of a multiple of 1/3 of the nominal module power. In the case of repairing single interruptions, the recovered power reaches more modest values, up to 6 percentage points of the power prior to the repair. This article also shows the benefits to module fill factor depending on the repairs made and discusses metastable interruptions and the occurrence of new interruptions that can occur after initial repairs are made. A classification of single interruptions is proposed based on their type, and several methods to determine their location are described, highlighting one in particular for its simplicity and low cost. Finally, the relevance of carrying out a total repair (twin and single interruptions) or a partial repair (twin interruptions only) is discussed.