POTENTIAL-INDUCED DEGRADATION: MEASUREMENT AND MODELING OF PROGRESSION UNDER FIELD CONDITIONS

摘要

Potential-induced degradation (PID) is a critical failure mode in today's photovoltaic (PV) system architecture with very large to catastrophic impact on PV-module performance and energy yield. Potential-induced shunting (PID-s) is one of the most severe types of PID leading to shunting of p-type silicon solar cells. Previously, the kinetics of PID-s was investigated in detail and a preliminary model was presented describing the progression of the shunt resistance (R_sh) of fielded modules. In this work R_(sh) measurements of mini modules that were exposed to field conditions and a high negative potential at an outdoor test site for one full year are presented and compared to model calculations. In addition the performance decrease of PID-s prone 60cell PV-modules installed on the negative end of a positively grounded module string is shown and the shunt progression simulated. The modeled R_(sh) progressions are in good qualitative agreement with the measured data. Nevertheless quantitatively there are clear differences between the measured and simulated R_(sh) progressions. In order to improve the calculation results the origin of these differences is analyzed.