Voltage-based hot-spot detection method for PV string using projector

This paper proposes a voltage-based hot-spot detection method for PV string using projector. Hot-spots form in solar cells at defects causing high carrier recombination rate, it appears as high reverse leakage current of p-n junction when solar cells are partial shadowed. Using this characteristic, authors previously developed a Voltage-based hot-spot detection method to quickly identify and characterize the severity of module hot-spot. The validity of this method has been confirmed. However, previous experimental results were show for just one module. In this paper, experiments are done on plural modules in string. From the result, this method works effectively for PV string. It provides the possibility of hot-spot inspection after modules are installed.