Detection and mitigation system for shading-induced hot spots in household crystalline silicon photovoltaic modules

Abstract

Hot spots have been a significant problem for photovoltaic (PV) installations until the present. Hot spots reduce the power production performance and speed up cell degradation of the PV system. Hot spotting is a reliability problem where mismatched cells heat up due to the reverse biasing of these cells and cause permanent damage to the PV panel. Hot spot occurrences are due to several factors such as shading, panel defect, electrical characteristics mismatching, and bypass diode failures. Bypass diodes are used as a protective device to reduce the severity of cell mismatching, particularly the effect of overcurrent per cell, but these can sometimes be inefficient for hot spot prevention. Through a camera and an IR thermal sensor, the hot spot detection technology implementation is possible with an Arduino-based program of which the results of the hot-spotted (affected strings or cells) are analyzed using Simulink. Furthermore, to mitigate the effect of hot-spotting in the cells, a modified transistor circuit is configured to carry the excess currents running in the cells due to overcurrent (OC). The solutions presented have considerably improved the performance and power output of the solar panels studied through the system’s corrective actions. It has been observed that there was an increase in the attention given to the solar panels by having been able to check which part of the panel’s cells were affected by hot spots as well. The proposed system design can be used in households that rely moderately on photovoltaic systems for energization.