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Extreme Testing of PID Resistive c-Si PV Modules with 1500 V System Voltage
P. Lechner, J. Schnepf, S. Hummel, D. Geyer, J. Wittfoth, R. Merino Martínez, P. Sánchez-Friera
EVA, PV Module, Polyolefin Encapsulation, PID Testing, Service Life Testing
Photovoltaic Modules and BoS Components
Subtopic: PV Module Design, Manufacture, Performance and Reliability
Event: 37th European Photovoltaic Solar Energy Conference and Exhibition
Session: 4BO.12.3
792 - 795
ISBN: 3-936338-73-6
Paper DOI: 10.4229/EUPVSEC20202020-4BO.12.3
0,00 EUR
Document(s): paper


The recent trend to increase the PV system voltage from 1000 V to 1500 V implies a higher PID stress level for the PV modules. This raises the question whether the modules might face PID problems caused by 1500 V system voltage during long-term field operation. Particularly, the IEC TS 62804-1 PID test does not provide a correlation between accelerated chamber testing and outdoor field operation. In this work, we follow the principle established for thin film modules according to the IEC TS 62804-2, where the transferred charge is the metric for the PID stress load. Furthermore, in order to transfer charge as fast as possible during lab testing, extreme PID testing conditions were applied. Test modules were manufactured combining two types of c-Si cells, “more PID stable” and “less PID stable”, with three types of encapsulation material, EVA1, EVA-2, and POE respectively. Surprisingly the IEC standard test could not differentiate the PID susceptibilities of the test modules. Even prolonged testing did not provoke a further degradation. Dropping leakage currents due to a blocking anode effect are suspected as the root cause for the observed, but misleading PID stability. In contrast to this, a clear differentiation of the module´s PID susceptibility was possible with our extreme test conditions. The transferred Coulombs under real outdoor conditions were measured at the ZSW test field for a whole year. With this information, the PID service life could be predicted. Modules based on POE are predicted to stay free from PID during a service life of 40 years.