Analysis of Reverse Stress in Potential Induced Degradation Affected PV Module Under Partial Shading Conditions
Abstract
Potential induced degradation (PID) is a detrimental failure mechanism that has gained greater attention in medium and large-scale photovoltaic (PV) plants in a recent decade. PID reduces shunt resistance and increases the recombination diode's reverse saturation current. As a direct consequence, the efficiency of PID affected module experiences a substantial decline, often leading to module failure well before their expected operational lifespan. Further, when a PID affected cell of a module is partially or entirely shaded, reverse stress is observed across the shaded PID cell, which ultimately affects the module's reliability. This paper presents an analysis of the reverse stress across the shaded cell encountered in PID affected PV module under partial shading conditions. The findings suggest that the high reverse current flows through the PID affected cell under partial shading conditions as compared to partially shaded healthy cell. The reverse stress current across the shaded cell depends on the value of its shunt resistance. By understanding the impact of reverse stress on PID affected modules, further degradation of PV modules can be prevented, improving the performance and overall efficiency of the PV system.
Keywords
Potential induced degradation (pid), Partial shading, Reverse stress, Reliability