Finding Defective Panels in Solar Farm using Drone Electroluminescence




Solar photovoltaic (PV) are getting adopted at an ever-increasing rate with increasing project scale. With a tremendous and growing amount of PV assets available in the market, it is essential to ensure that the PV assets are working optimally to prevent financial and environmental losses. Defective PV modules in the field can cause performance drop of the PV assets and must be quickly identified and replaced.  The proposed technology enables fast and accurate identification of defective solar PV modules at solar farms. The core technology comprises (a) front end: use of advanced drone electroluminescence (EL) for fast inspection, in which the whole process/workflow of drone EL inspection and dedicated hardware required for high-speed inspection are patented. (b) back end: post-processing of EL images using Quantitative Electroluminescence Analysis (QELA) algorithm for power loss prediction, enabling accurate identification of defective panels. The technology owner is seeking partners to collaborate through test-bedding in actual environment.


Electroluminescence (EL) is able to capture unique signature emitted by the PV modules and hence able to detect most of the defects in solar system.  Conventional drone inspection is using visual and thermal imaging. Visual imaging is used to mostly detect front surface defects such as soiling, glass breakage, etc. Thermal imaging detects heat signature emitted by the PV modules. It is mostly used to detect problem caused by external factors such as shading and soiling. It can detect a limited amount of internal defect such as bypass diode failure. EL imaging on the other hand can detect almost all kind of PV modules defects such as cell cracks, PID, corrosion, soldering disconnection, etc.  Drone EL inspection will ensure optimal system performance by quickly and accurately identifying defective PV modules in the field.  The Quantitative Electroluminescence Analysis (QELA) is the only algorithm in the world that complies with IEC 60904-13:2018 standard through the round-robin study of 17 labs around the world.


The drone electroluminescence inspection can be used at various stages of PV lifecycle: Year 0: After the completion of the PV system to detect any fault with the installation and to establish a baseline of PV system health. Year 2: Before the end of warranty by EPC contractors or defect liability period to find all defective modules for warranty claims with EPC. Year 5: As first preventive maintenance to identify defective modules that suffer mid-life failure. Year 10: As second preventive maintenance to identify defective modules before the end of 10-year module material warranty given by the manufacturer.  Ad-hoc test: When there is a suspect of defects in the PV system, the drone EL can be used to clearly identify the defective components for corrective maintenance.  Any point for asset transaction: Conduct technical due diligence using our comprehensive module level inspection. Force majeure incident: The technology can be used for damage evaluation for extraordinary maintenance.


Improve system performance by replacing defective modules Provide clear evidence of module defects to support warranty claims or insurance claims Provide clear data of PV assets status to facilitate asset transaction Provide technical due diligence to bankability and insurability study of PV assets