Practical guide Solar Panel Thermography.

1 Practical guideSolar Panel advice and growth of the Solar industry brings an ever expanding base of Solar installations. While many Solar panels are expected to provide a 20 year life span, this is often not the case with myriad of Solar Panel manufacturers supplying products of varying quality. Until the development of Solar thermography technology it was time consuming and difficult to troubleshoot and assess the quality of Solar Panel manufactures four models of thermal cameras with features specially optimized for the surveying and troubleshooting of Solar panels . The unique Testo Solar Mode feature simplifies the on-site work and saves time by automating the custom setup steps required. The Testo TwinPix feature uses dual images, a visual image overlaid with the thermal image, to allow precise fault location. Our patented SuperResolution feature effectively quadruples the resolution of the Solar Panel images displayed in our software and thermal cameras and software are fully compliant with the 2014 Infraspection Institute Standard for Infrared Inspection of Installed Photovoltaic (PV) :Advantages of thermographic Solar Panel testing.

2 4 Origins of Solar cell failures. 7 How to avoid common inspection errors. 11 Thermal camera choices. 14 Testo Solar mode thermal cameras. 17 thermography training providers. 18 4 ThermographyAdvantages of thermographic Solar Panel testing. Quality assurance of Solar Panel panels come from many sources around the world, and their quality varies between manufacturers and product installation quality depends also on the installer s competence. In short, the best way to prove that the Solar Panel installation is delivered free of defects is the the thermal imaging analysis of the site installation. The thermal imaging report is meant to protect both the customer and the of the power yield Solar system ROI calculation often assumes 20 years of power production. As the panels age the gradual loss of power is calculated as well. These calculations can t predict system deterioration caused by lightning storms, Panel cell overheating and other component assure optimal continuous Solar power production, thermography scans should be performed at regular intervals to assess preventive maintenance example, when modules overheat due to shade, defective cells, or substrings consuming instead of producing power, the module efficiency can drop by per Kelvin.

3 A Panel temperature rise of 18 F (10 C) as compared with an average temperature of other panels can lower the power yield by as much as 5%.5 Fig. 1: Thermal irregularities point to a possible loss of electricity imaging helps to identify mismatched panels where high performing modules are impeded by lower performing modules and overheated important inspection should be before the expiration of the Solar manufacturer s warranty to make sure that any defective panels can be replaced under the warranty of can easily incorporate thermography into their quality assurance programs. This helps to develop future business by scheduling preventive thermal first inspection should be done at the end of the initial installation as a proof of proper function to protect both the contractor and the systems are outdoor electrical installations exposed to stresses of wind, rain, snow, melt and freeze cycles, and UV radiation.

4 Such exposure can result in weathering and accelerated corrosion. A Testo thermal camera is the key tool to identifying thermal inverters and other high wattage components should have sufficient cooling to prevent overheating failures that might lead to fires. Again, the thermal camera will help here to identify overheating components and lines in the electrical diagnostic is a safe, non-contact measurement method to check groups of circuits and Solar panels . The thermal irregularities are apparent on the camera s screen and dual images can be saved to the report. The Testo TwinPix feature uses dual images, a visual image overlaid with the thermal image to allow precise fault bypass diodes can be easily located with this feature and the thermal image provides electricians with a perfect guide for the diode systems use high voltage wiring, but thermal inspections are done from a distance and never come in contact with live wiring, yet are still able to pinpoint overloads and short circuits by their thermal signature 2: Faulty modules after a lightning of Solar cell image cameras look for Panel hotspots.

5 Overheated cells can damage the casing material and cause delamination. Where do the hotspots come from? Shade on the module or a defective cell can change the module from power production to power consumption resulting in heating the cell which will show as a hotspot in the thermal image. A defective or mismatched bypass diode may cause the same Solar Panel hotspots create two issues: Fall in overall power production since cells consume power instead of producing. Power consumption continues to heat up cells and affect the production of neighboring Solar Panel diagnostics, the US Infraspection Institute Standard calls for the presence of at least 650 W/m Solar radiation to differentiate the Solar Panel thermal Solar Panel faults Defective bypass diodes Short circuits and falling connec-tions Penetration of moisture and/or dirt Cracked cells or glass cracks Failed or disconnected modules Mismatched panels with different capacities Loose contacts and wiring faults Wear and tear8 ThermographyImage samples of common defects.

6 (Fig. 3) This thermal image illustrates three common issues with defective individual cells and substrings. The connection point in the image shows visible heating, suggesting that testing is required.(Fig. 4) panels might be non-function-ing due to miswired panels or worn / defective cables. This condition is in-dicated when the entire Panel is hotter when compared to others.(Fig. 5) Delamination due to external damage or substandard Solar Panel quality. The EVA protective layer may delaminate, micro-cracking and cell rupture may appear during transpor-tation or installation due to physical stress. While the micro-cracking is not critical, cell rupture (Fig. 6) can reduce performance: Moisture seeping in may lead to cell corrosion and loss of per-formance. Testo thermal cameras can detect this before the Panel s outer layer shows a milky 3: Samples of defective cells and sub-strings.

7 Defective substring Defective individual cell Connection pointFig. 4: Panel 5: Delamination on two 6: Cell of Solar Panel Table below (Fig. 7) explains images of common 7: Schematic diagram of infrared images and possible Panel representationDescriptionPanel overheating as compared with the other pattern for a string of cells. Patchwork pattern where individual cells are randomly distributed and significantly overheating of a part of a heat pattern or overheated at specific of a single defectsPanel is not circuit in a cell is not crack or other electrical and mechanical thermal cameras are very useful for reviewing and checking the other electrical parts of the Solar system aside from the Solar panels . Loose connections and corrosion can create resistance, creating a specific heat signature detectable by the thermal thermal camera will point you to: Corroded contacts or connectors Inverter issues Loose contacts Overheated connection pointsFig.

8 8: Left inverter is significantly 9: Overheated DC 10: Overheating of electrical to avoid common inspection good thermography inspections select a clear, dry day. Measure Solar radiation with an appropriate light meter to make sure that the Solar radiation is at or above 650 W/m . In direct sunlight Solar panels work at full capacity and damaged Solar cells will show clearly on the infrared the Solar radiation changes during the measurement, for example, due to clouding (Fig. 11), the infrared image will be unusable. For the best possible temperature differentiation it is recommended to carry out measurements when the outdoor temperatures are low ( morning or evening). : Visible cloud reflections. panels might also be affected by wind panels mounted on free standing Solar racks can have thermal images taken from the back of the Panel (Fig.)

9 13) This method avoids measurement errors and eliminates heat source reflections. The heat transfer is sufficient to allow the determination of temperature distribution of the Solar cells on the back of the Solar Panel . Fig. 12: Sample of proper camera alignment for the measurement of Solar 13: Thermal image taken from the back of the angle and viewing angle and position are important for good thermographic measurement. The camera must be well aligned with the Solar Panel . Horizontal alignment 60-90 , and the vertical alignment should be close to the angle of Solar the thermographer s shadow aligned with the sun in Fig. 12. Viewing angle measurement errors can cause incorrect temperature and false reflection skilled thermographer should be able to detect reflected heat sources by camera movement and the angle of view do not necessarily mean that cells are every cell with a hotspot is defective.

10 For example, the Panel mounts and connection points will show up due to heat transfer to the Panel s surface (Fig. 14). panels with significant differences should be checked for dirt and and span recognition is dependent on camera level and span adjustment. Automatic settings in thermal cameras detect the hottest and coldest point and adjust color grading across the entire range (Fig. 16 and 17). This wide spread eliminates any relevant temperature differences and may cause errors. Testo thermal cameras come with a unique Solar Mode to alleviate this problem. Testo Solar Mode simplifies the on-site work and saves time by automating custom setup 15: The Testo TwinPix image overlay shows dirt caused by bird droppings at the worst 14: Connection points on the back are highlighted by 17: Manual 16: Automatic be successful with Solar Panel thermal imaging, the right thermal camera must be selected.