The effect of reduced shunt resistance and shading on photovoltaic module performance

In analyzing Photovoltaic (PV) performance degradation modes, the effects of low shunt resistance and temporary partial or complete shading are often neglected. These factors can however be detrimental to the performance of these modules and specifically, shading may cause irreversible cell damage if the module is not electrically protected. In this study the effects of reduced shunt resistance and shading on PV module performance were investigated. Furthermore, the effect of shading is analyzed for various cell shunt resistances. The ultimate objective of the study is therefore to quantify the inter-dependence of the effect of reduced shunt resistance and shading on PV module performance. This paper investigates the effect of reduced shunt resistance, R-sh, on PV module performance, the effect of shading on module performance and finally discusses the correlation between the effects of reduced shunts and shading. Results obtained indicate that there exists such a correlation.