Area 7: Performance and Reliability of PV Modules ESTIMATING THE PERFORMANCE OF PID-INFLUENCED PV MODULES FROM QUANTITATIVE ELECTROLUMINESCENCE MEASUREMENTS

In a collaborative effort involving SERIS, NREL, and Trina Solar to study PV modules potential-induced degradation (PID), testing fields have been set up under three different climates: tropical, subtropical, and sub-arid climates in Singapore, Changzhou (China) and Golden (CO, USA) respectively. Each testing site has six groups of modules developed by Trina Solar with different grades of PID resistance ranging from weak to strong. Among all the locations, Singapore presents the most severe conditions for module PID. At SERIS, the impact of potential-induced degradation (PID) on PV module performance is quantitatively analyzed using spatially resolved electroluminescence (EL) imaging. Indoor EL images and I-V characteristics were measured every month. In this work, the EL method is applied as metrological tool to predict the module power losses due to PID. Firstly, all images taken (Figure 1) were corrected for camera and perspective distortions (Figure 2). After correction, the intensity distribution of each cell, relative to its initial values is analyzed. To translate the relative EL intensity to cell performance, a simplified equivalent circuit is used to calculate the relative changes on the effective I-V curve (Figure 3). The metrological performance of this method is quantified through comparison with I-V curves, obtained from indoor flash tests (Figure 4).