Aerial thermographic inspection of solar plants
A drone with a thermal camera flies over the plant and shows which modules are running hotter than normal. It is the fastest way to find hotspots, failed diodes and damaged cells without stopping generation.
What drone thermographic inspection is
Almost every electrical defect in a photovoltaic module turns into heat. A cracked cell, a burnt diode or a poor connection makes the current meet resistance, and that area gets hotter than the rest of the panel. The infrared camera sees this temperature difference, which is invisible to the naked eye.
With a drone, the inspection covers the entire plant in a short time and while the plant is generating, the condition in which defects show up. On foot, module by module, the same work takes much longer and misses faults.
How the inspection works, step by step
1. Flight planning
Plant layout, string map and flight plan. The flight is carried out under strong sun and clear skies, when the plant is generating close to its maximum and temperature differences are clear.
2. Flight with thermal and visual cameras
The drone flies along the rows, capturing infrared and regular images. The visual image helps separate electrical defects from soiling, shading or vegetation.
3. Image analysis
Each thermal anomaly is located within the plant and classified by its probable type of fault.
4. Report
A list of the modules with anomalies, with each one's location in the plant, images and probable fault, to guide the O&M team.
What the thermal camera finds
Hotspots
A cell or section of the module much hotter than the rest, caused by a damaged cell, persistent shading or a manufacturing defect. If ignored, it can burn the backsheet.
Failed bypass diodes
When a junction box diode conducts all the time, a strip of the module, usually one third of it, appears evenly heated and that part stops generating.
Cracked cells and microcracks
Cracks that already affect current flow appear as hotter cells. Small microcracks that do not heat up yet may require another type of test to be confirmed.
Soiling, shading and vegetation
Accumulated dirt, bird droppings and tall weeds cause localized heating and generation loss. These are maintenance issues that cleaning solves.
Broken glass and damaged modules
Modules broken by hail, impact or handling during cleaning show an irregular thermal pattern. With cracked glass, the module keeps generating, which is why the breakage goes unnoticed in the generation curve.
Strings and connections
An entire row cooler than its neighbors indicates a disconnected or faulty string. Poor connectors appear as hotspots on the cables.
After the inspection: repair, warranty or disposal
The report separates what the O&M team can fix in the field, such as cleaning, vegetation trimming and connector replacement, from what requires replacing the module. Modules with manufacturing defects may qualify for a warranty claim; modules damaged by hail or windstorms may go into the insurance process.
Modules removed from the field become plant waste and need a proven destination, with an MTR (Brazil's mandatory waste transport manifest) during transport and a Certificate of Final Disposal (CDF) after recycling. During removal, keep in mind that a broken module still generates voltage in the sun and that cracked glass cuts: gloves, pallets and a protected glass face.
This is where SunR works: it recycles the rejected modules through a 100% mechanical process and delivers the MTR, CDF and disposal report for each batch. After a loss event, the volume can be large: in Paracatu, Minas Gerais, a storm in 2023 took around 100,000 ENGIE modules out of operation, 2,900 tonnes recycled by SunR. Pickup has no minimum volume, from homes to solar plants.
Why carry out a thermographic inspection
No plant shutdown
The flight takes place with the plant in operation. There is no shutdown and no generation loss during the inspection.
The whole plant, not a sample
The drone covers every module. Isolated defects that a sample-based inspection would miss show up on the map.
Priorities for O&M
Each anomaly comes located and classified, so the field team goes straight to the modules that need attention.
Evidence for warranty and insurance
Thermal and visual images with location help document manufacturing defects and loss-event damage.
Further reading
Hail at the plant: what to do with the modules (in Portuguese)
The step-by-step after the loss event, from the damage survey to the destination of the broken modules.
Ver maisBroken solar panel: repair, insurance or disposal (in Portuguese)
When it can be repaired, when to file an insurance claim and when the module goes to recycling.
Ver maisWant to know which modules in your plant are defective?
Tell us the size of the plant, its location and what you are seeing in generation. SunR will reply with the inspection plan.
Frequently asked questions
What does drone thermographic inspection detect in solar plants?
Hotspots, failed bypass diodes, cracked cells, disconnected strings, poor connectors, soiling, shading and broken modules.
Does the plant need to be shut down for the inspection?
No. The inspection is carried out while the plant is generating, which is the condition in which defects show up on the thermal camera.
Does thermography find microcracks?
It finds the cracks that already affect current flow and heat up the cell. Small microcracks that do not heat up yet may need another test to be confirmed.
Under what conditions is the flight carried out?
Under strong sun and clear skies, when the plant is generating close to its maximum. On cloudy days, temperature differences are too small.
What should be done with the modules that fail the inspection?
Manufacturing defects may qualify for a warranty claim, and loss-event damage for the insurance process. Modules removed from the field become plant waste and must go to licensed recycling, with an MTR (Brazil's mandatory waste transport manifest) and a CDF (Certificate of Final Disposal). SunR recycles these modules, with no minimum volume.