Key takeaways:
TT Vision highlights the use of RGB, thermal infrared and electroluminescence imaging as complementary tools for PV module inspections in a technical paper
According to the research, combining thermal and EL imaging can help identify the root causes behind hotspots and other module anomalies
AI-based analytics can prioritize maintenance actions based on defect severity, energy losses and operational risks, it adds
A hotspot visible in a thermal image may indicate a problem in a PV module, but it does not necessarily reveal its cause. The underlying issue could range from a microcrack or interconnect failure to potential-induced degradation (PID) or another internal defect, requiring additional diagnostic tools for accurate identification.
Malaysia-based TT Vision has released a technical paper that explores how combining RGB imaging, thermal infrared (IR) imaging, and electroluminescence (EL) imaging can improve defect detection and maintenance decisions in utility-scale solar systems. Each technology reveals different types of defects, making them complementary rather than competing inspection methods. The approach integrates these inspection techniques with drone platforms to enable faster diagnostics and more efficient maintenance planning for utility-scale PV plants.
RGB imaging is effective in identifying visible anomalies such as broken glass, soiling, bird droppings, corrosion, vegetation encroachment, and other surface-level defects. Thermal imaging, on the other hand, is commonly used to identify hotspots, diode failures, and abnormal temperature distribution. The thermal imaging can reveal where an anomaly exists, but cannot always explain the underlying cause.
This is where EL imaging comes into play. With this technique, defects such as microcracks, broken cells, interconnect failures, PID, light and elevated temperature induced degradation (LeTID), and delamination issues can be identified. These defects are otherwise difficult to detect using visual inspections alone. Combining thermal and EL imaging enables operators not only to detect the problem, but also to understand the root cause.
The paper presents an example of EVA delamination. The same defect appears differently in RGB imaging, thermal, and EL imaging. While RGB reveals visible signs of degradation, thermal imaging indicates temperature variation, and EL identifies the electrically inactive region within the module. Together, these 3 inspection techniques provide a comprehensive assessment of a module’s condition.
Identifying defects is only one part of the process. Large solar plants can contain hundreds of thousands of modules, generating significant volumes of inspection data. To address this challenge, TT Vision combines inspection results with AI-based analytics that classify defects according to their severity and operational impact.
The defects are grouped into categories such as immediate action, near-term repair, and routine maintenance. Prioritization is based on factors including safety risks, expected energy losses, and financial impact. This enables plant operators to focus maintenance efforts on issues that pose the greatest risk to system performance.
As solar assets continue to increase in size and complexity, inspection technologies are also evolving beyond simple fault detection. By combining RGB, thermal and EL imaging with AI-driven analytics, the industry is moving toward more predictive and data-driven maintenance strategies.