In-the-field PID related experiences

Abstract

Potential induced degradation could considerably decrease the performance of photovoltaic systems which operate at high DC voltages. Nonetheless, methodologies for dealing with it in field are not clearly yet defined. This work explains the kinetics of this phenomenon in the field and presents an assessment of its occurrence, detection and prediction in real PV installations. Measurements of the instantaneous operating voltages of the photovoltaic module as a verification routine and predictive maintenance is proposed here as a reasonable and most accurate way of analyzing the actual power losses of the photovoltaic system related to this kind of degradation, as well as detecting and predicting it. Potential induced degradation prevention and recovery have also been carried out by the application of reverse voltage during the night, showing the validity of this technique. A literature review for the PID dynamics of different kinds of photovoltaic cell technologies and development of PID test methodologies and standards is also presented.