Solar energy is one of the renewable sources that can be found in abundance. The use of solar panels leads human beings to make use of this prime source. But the maintenance of these panels requires a proper check on them to remove the defective ones and avoid any decreased amount of energy production. So, drones are used to keep a check on the panels for more effective performance. Drone inspection of solar panels is in practice which leads to proper check on the panels. And proves to be a long-term goal.
Drones are basically fit with infrared cameras to systematically record the whole area. Where panels are placed and analyse the region. It helps to focus on the spots where the solar panel is not taking the heat as much as it should. In addition, it filters all the defective cells which need maintenance.
Five common solar panels issues for drone inspection are:
- Hot spots- these are places on the panels that get overloaded. And ultimately get heated up, which can lead to short-circuiting. This may reduce panels performance and lifespan.
- Microcracks- microcracks don’t show instant production loss but generally grow over time. Large microcracks lead to heavy production loss. These result from low quality or when carelessly handled.
- Snail trial contamination- after some years of production, the discoloration in the panel is known as snail trial production. It can be cause due to the silver metallization paste in the cells. And also by the microscopic cracks made in the panel.
- PID effect- potential induced degradation. The difference in the panel and earthing voltage can be consider as the main reason for its occurrence. The overall performance is degrade of the panel, and the aging of the panel gets accelerate.
- Internal corrosion and delamination- It is the most common issue. As it is cause by an internal drain, moisture, or dust leading to internal corrosion. If proper attention is not given, then dark spots can be seen in the panel. Which leads to a decrease in output production.
Drone Inspection vs. Ground inspection:
The manual labour or ground inspection cannot beat the inspection done by drone. As it will not provide the individual spotting of the cells with a good resolution. Ground inspection can, however, not compete with drone inspection in mapping the whole solar panel area.
Advantages of drone inspection:
- Professional drone inspector: a professional drone inspector can use drones more efficiently. To make sure every cell works at its maximum. A professional inspector has knowledge and experience in fieldwork.
- Time saver: It saves a huge amount of time when there are big solar panel fields.
How does drone thermal imaging help PV inspection?
Aerial thermography is require for PV system commissioning and maintenance due to the level of detail package. And the speed it can provide. The thermal cameras also referred to as LWIR, detect infrared bands. Making them able to see through total darkness, fog, and smoke. Cameras with aerial thermal imaging make inspection quicker. An RGB camera detects other issues like soiling, animal nesting, and shading. Pairing both thermal and RGB cameras together with drones provides more effectiveness.
For PV inspection, the medium of video analysis is also a problem because of low quality, storage problems, geotagging is not possible. And radiometric analysis is also not possible.
Common impairment symptoms generally found by PV testing technicians manually inspect:
- The series loss is cause by excessive resistance, and the resistance results in degradation and damage.
- A shunt results in power losses by an alternate path or short-circuiting a cell. This diversion results in the heating of that particular component.
- The interconnection of solar cells that do not have the same properties and experience different conditions.
- The reduction in the current but not in voltage caused by degradation or soiling refers to reducing current losses.
- Due to the less efficiency of group cells or by a short bypass diode, reduce voltage loss is cause.
How to use drone thermal imaging for solar inspections?
The results from professional drone inspection, which draws from the combination of RGB. And thermal imaging data, a technician of PV testing can execute more effectively the manual electrical testing on impaired PV panels. Thus, the training is require as much as in IV Curve Training.
PV Inspection includes both qualitative and quantitative analysis. Quantitative analysis includes the temperature data from the thermal sensor—qualitative analysis. Visual post-analysis of thermal and RGB images such as shattered module. There are various factors that affect the inspection.
The three factors to be consider by aerial thermographers in the field during post-processing:
- Environmental conditions- the ideal weather conditions need to be taken into account before the pre-flight preparation of drones. Humidity, high winds, atmospheric currents act as a hindrance to the inspection and the quality of the image.
- Hardware considerations-
- Flight speed: For 100 to 1000 acres sites. Usage of fixed wings allows higher speed, increase in coverage, and flight times.
- Integration: In a PV system, the redundancy. And the situational awareness can be expand by the usage of both RGB and thermal (the dual sensors).
- Data accuracy- emissivity is consider the ratio of the actual amount of electromagnetic radiation emitt by an object. To the amount emitted by an ideal blackbody at the same temperature. Post processing caused by emissivity heavily influences data accuracy. As the inspection takes place under high software programs, with specific high-resolution panels in PV panels which emphasize anomalies, etc.
Conclusion
Drones in solar industry have set the revolution. As countries and states are increasingly moving towards making the most use of renewable energy by the usage of solar panels. The need to take care of the whole asset inspection has arisen. And to maintain these, different strategies are adopt. The thermal drone inspection leads the company towards the usage of various tech devices. And also leads them towards long term goals.