Solar Farm Inspections

 In the growing field of solar panels, quality assurance is of fundamental importance.The failure-free operation of the panels is a prerequisite for efficient power generation, long life, and a high return on the investment. To ensure this failure-free operation, a fast, simple and reliable method to evaluate a solar panel's performance is required . This should be applied both during the production process and after the panel has been installed.

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The use of thermal imaging cameras for solar panel evaluation offers several advantages:
  • Anomalies can clearly be seen on a crisp thermal image and unlike most other methods 
  • Thermal cameras can be used to scan installed solar panels during normal operation.
  • Thermal cameras also allow to scan large areas within a short time frame.

 

 
Problematic areas on different material modules
 
 Evaluation of defective cells
 

What you can see in the thermal image:

If parts of the solar panel are hotter than others, the warm areas will show up clearly in the thermal image. Depending on the shape and location, these hot spots and areas, can indicate several different faults. If an entire module is warmer than usual that might indicate interconnection problems. If individual cells or strings of cells are showing up as a hot spot or a warmer ‘patchwork pattern’, the cause can usually be found either in defective bypass diodes, in internal short-circuits, or in a cell mismatch.

Shadowing and cracks in cells show up as hot spots or polygonal patches in the thermal image. The temperature rise of a cell or of part of a cell indicates a defective cell or shadowing. Thermal images obtained under load, no-load, and short-circuit conditions should be compared. A comparison of thermal images of the front and rear faces of the module can also give valuable information. Of course, for correct identification of the failure, modules showing anomalies must also be tested electrically and inspected visually.

The left thermal image below, shows an example of the so-called ‘patchworkpattern’,which indicates that this panel has a defective bypass diode
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On the right image above, the red spots indicate modules that are consistenly hotter than the rest,indicating faulty connections
 

 Inspections with a thermal imaging camera can be used as quality control in the installation phase, followed by regular checkups - facilitate complete and simple system condition monitoring. This will help to maintain the solar panels' functionality and to extend their lifetime. Using thermal imaging cameras for solar panel inspections will therefore drastically improve the operating company’s return on investment.

Which other PV companies use thermal inspection?

  • Schoten, Belgium, based Ikaros Solar
  • German company SOLON
  • Solartechnik Stiens Germany