Title:	Technical Considerations Resulting from Photovoltaic Module Heating During Electroluminescence Inspection
Author(s):	L. Koester, E. Vallarella, A. Louwen, S. Lindig, D. Moser
Keywords:	Performance, Electroluminescence, Inverter
Topic:	PV Systems Engineering, Integrated/Applied PV
Subtopic:	Operation, Performance and Maintenance of PV Systems
Event:	8th World Conference on Photovoltaic Energy Conversion
Session:	4DO.4.4
Pages:	1112 - 1118
ISBN:	3-936338-86-8
Paper DOI:	10.4229/WCPEC-82022-4DO.4.4
Price:	0,00 EUR
Document(s):	paper, presentation

Abstract/Summary:

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Electroluminescence imaging experienced uprising use in the last years. In future photovoltaic plants the time-consuming connection of power supplies to photovoltaic module strings could be overcome by use of inverters with bi-directional functionality, allowing backpowering of connected module strings directly. During backpowering, the limits of the power supply must be considered. As temperature influences the open-circuit voltage, it is a crucial parameter to remain in these limits. The EL inspection itself impacts the solar cells temperature, as they warm up during the process, resulting in a shift of open circuit voltage. This work investigates the heating of a hetero junction photovoltaic module during electroluminescence inspection. The saturation temperature is estimated by energy balance calculations and experimentally verified to be around 20°C, with resulting voltage drop above 2 V. The importance of this is not only to verify that the measurement is within the limits of the power supply but also to consider changes of the recorded luminescence intensity due to the temperature, shown to have a decrease of up to 4 %.