Title:	Fundamental Study on Open Fault Detection Technology of Bypass Circuit of PV Module with IR Camera
Author(s):	S. Nishikawa, N. Fujita, H. Kuroda
Keywords:	Solar Radiation, Fault Detection, Bypass Circuit, IR Camera
Topic:	Photovoltaic Modules and BoS Components
Subtopic:	PV Module Design, Manufacture, Performance and Reliability
Event:	37th European Photovoltaic Solar Energy Conference and Exhibition
Session:	4CO.4.5
Pages:	914 - 918
ISBN:	3-936338-73-6
Paper DOI:	10.4229/EUPVSEC20202020-4CO.4.5
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

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When a bypass circuit of PV module is open and performance of solar cells drop by partial shadow, abnormality, and so on, the temperature of those cells increase and become hotspot. Observation of module surface temperature with IR camera is very popular technology for finding hotspot. However, a hotspot does not occur with only existence of open fault of bypass circuit, and temperature does not increase under low irradiance. In our proposed technology, the pseudo sine-wave voltage with DC bias is applied across the PV string. The temperature of the faulty part without bypass circuit changes in accordance with change of applying voltage. The temperature change is observed with an IR camera, and only the fault position is identified by the frequency analysis of temperature change. However, temperature change is influenced by mainly magnitudes of irradiance and applied voltage. To clear their effect, we conducted a fundamental test by using a small string with a dummy open fault of bypass circuit. As a result, when irradiance is more than 200W/m2 and applied voltage across a string is bigger than open circuit voltage Voc of a PV module, we can find an open fault position in a string.