5. 3 Operation, Performance and Maintenance of PV Systems
Partial Shading, Temperature Coefficient, Efficiency, Hot Spot
Summary / Abstract:
Partial shading of photovoltaic (PV) modules leads to mismatch losses which cause local hotspots. Hotspots can lead to various failure mechanisms, hence, power degradation in PV plants. This work investigates the temperature sensitivity of field-aged multicrystalline silicon PV modules under uniform partial shading conditions. Thermal images suggest that hotspots are localized to busbars at the shaded area. The results estimate that, the temperature coefficient of Vmpp (Vmp) of the field-aged PV modules under STC ranges from -0.41 %/ to -0.48 %/. However, under partial shading conditions, the absolute variation in the Vmp is >2.00 %/ for the 3 field-aged PV modules studied. The results for the temperature coefficient of Impp (Jmp) ranges from ca. -0.08 %/ to 0.01 %/ and ca. -1.00 %/ to -0.90 %/ under non-shading and partial shading conditions, respectively. However, the severity of the temperature sensitivity under partial shading conditions also depends on the degradation state of the PV modules.