Shunt Resistance Relation to Power Loss due to Potential Induced Degradation in Crystalline Photovoltaic Cells

Abstract

Potential Induced Degradation (PID) is expected to become more frequent with the increased system voltage of photovoltaic (PV) systems. Thus, a PID detection method is required to detect PID at an early stage in order to increase the reliability of PV systems and the lifetime of PV modules. In this paper, a relation between the shunt resistance and the power loss of a PV cell due to PID is derived for the development of a detection model from cell to module level. The results indicate a logarithmic relationship. In addition, a shunt resistance threshold, at which significant power loss starts to appear, is derived. The threshold is examined for various power loss levels and temperatures. The threshold was found to decrease with temperature with a near linear behaviour.