ECN publication
The hot string and the cool module : case study of fault detection in PV systems by means if IR photography
Published by: Publication date:
ECN Solar Energy 1-10-2001
ECN report number: Document type:
ECN-I--01-017 Other
Number of pages: Full text:
18 Download PDF  

IR photography was used for the inspection of a PV system on the fa├žade of a building. The IR photographs showed five PV modules having a temperature that was significantly higher than that of neighbouring modules. The open-circuit voltage and short-circuit current of the strings in the PV array were measured. It was concluded that a single module was connected in reverse in the string containing the hot modules. At the time the IR photograph was taken the PV inverter was not active and the PV array was effectively short-circuited. Thus the energy generated by the modules of the array was dissipated in the string with the module connected in reverse, which lead to the observed rise in the module temperature.The resulting current-voltage curves of the PV array are calculated using models of the electrical characteristics of multicrystalline Silicon modules.

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