Performance and Degradation Evaluation of PV Modules on the Substring Level by an In-Situ Electronic Device

As the number of photovoltaic installations increases, so does the interest in PV module degradation and failure mechanisms. We developed a novel electronic device for PV module substring voltage measurements that can be installed directly into the junction box of a module. The results of the first year of operation show the benefits of knowing the operating conditions on the substring level. By measuring substring voltages, we were able to identify modules with potential problems with measurements performed in a very short time interval in an early stage without the need of a thorough PV module characterization.