Thermographic analysis of photovoltaic systems
PV-Installation have low maintenance, but are not maintenance free!
Statistical analysis confirm, that many installations that are in O&M have also loses of over 3 % in one year. The reason are defects on cells, diode and connection on string level. If this fails are not corrected in a short time an installation could be have loses of over 6 % in one year. That means a lot of money for the investors.
Defective or malfunctioning photovoltaic systems cause high losses if the faults are not detected in time. A thermographic analysis helps to detect defective modules as well as other errors and thus make corrections possible in good time. Flying Detection offers a thermographic inspection of photovoltaic systems (open space, roof systems, etc.) with the help of a drone and professional equipment (high-resolution thermal imager, other cameras for optical examinations, etc.) to find damage and faults in the modules in the system and to document. This is a very effective, fast and cheap way to ensure the yield of a photovoltaic system.
Technology used in thermography
Thermography uses a FLIR model Vue™ Pro R high-resolution thermal imager that works well with an optical camera (Panasonic LUMIX TZ41 with 18 megapixel resolution) for best results. The cameras are mounted on a high-tech Octocopter AscTec Falcon™ 8, a drone that is designed for professional use and is specifically designed for inspections and surveying. The recorded photos are provided by GPS with the exact coordinates.
Module errors that can be detected:
- Hot spots
- glass breakage
- string error
- defective cells and substrings
- faulty or not connected modules / module failure
- Pollution and invading moisture (cell corrosion)
- Defective bypass diodes
- PID (potential-induced degradation)
Procedure for the thermography of a photovoltaik system
The thermographic investigation of photovoltaic systems with a thermal imager is a recognized method for testing photovoltaic systems. Since only trouble-free operation guarantees full performance, the modules must be checked at regular intervals for hotspots, etc. During operation, a drone equipped with a high-resolution thermal imager can quickly detect faults in the modules or in the interconnection. After evaluating the images, recommendations for action are made to ensure the safety and full performance of the PV systems. This extends the life of the system and recovers investment faster.
The thermography is based on the preliminary DIN VDE V 0126-23-3 (Non-Destructive Testing - Infrared Thermography of Photovoltaic Modules and Outdoor Installations). In this case, a minimum irradiation power of 600 W / m2 should be present in the module level, which is always checked before flying by means of an irradiance meter. At the same time optical and thermal images are recorded. The detected heat radiation is converted into temperature values and stored. These are displayed in color as a thermal image and then evaluated exactly using special software. By recording the optical images, it is possible to identify soiling or mechanical defects and to take them into account in the overall analysis of the plant.
The investigation of the PV system takes place during operation. Within a very short time an overview of the condition of the plant can be given. Subsequently, all module errors are documented and classified in a detailed report. Depending on the error, recommendations for action are issued. Thus, the loss of revenue can be minimized and losses avoided.
Advantages of infrared thermography with a drone:
- fast and effective
- execution during operation
- imaging thermogram with digital comparison recording
- data storage
- comparisons over longer periods possible
- even difficult-to-reach areas easily possible to investigate
Thermography of new and existing PV systems (maintenance)
A thermography of the photovoltaic system makes sense immediately after commissioning in order to detect defective modules and faults immediately and, if necessary, to be able to complain to the module manufacturer. Defective modules can be replaced immediately. But even during operation, the inspection and maintenance of the system is extremely important to register possible warranty claims in good time and to be able to exploit the full yield.