Thermal Inspection can include inspection cables, contacts, fuses, switches, inverters and batteries. This inspection supports preventive maintenance for failure prevention, system availability for power generation and inspection of the quality of Pv modules.
A detailed thermographic inspection and analysis may include thermal signatures, thus requiring a deeper understanding of thermal anomalies. It can be used for periodic inspection and to troubleshoot the causes of underperforming systems. A competent expert in PV power plants can carry out the inspection together with thermographers.
Thermographic Inspection Procedure
Inspection of PV power plants should be carried out in accordance with health and safety regulations during the commissioning and operation of the power plant. The recommended interval for Periodic Thermal Inspection, thermographic inspection is four years, but the intervals required for a specific installation should be compared with the PV plant owner or defined by national electrical regulations and safety regulations for electrical installations.
A second person should be present during the inspection of the PV plant and it should be carried out according to local safety regulations. The detailed inspection scope shall be defined prior to the inspection and agreed in writing between the parties involved.
The part of the system being assessed must be in thermal steady state and, if possible, free from partial shading. Contamination must be low and homogeneous and must not cause partial shading (e.g. bird droppings, leaves, vegetation) in order to avoid thermal effects.
If contamination or partial shading due to e.g. bird droppings is observed on the PV modules, it is recommended to clean the entire SPP site before the inspection. Note that the performance of the system may change as a result of the cleaning. Ensure that the modules are in thermal steady state before performing the infrared imaging inspection and after cleaning.
Collecting IR (Infrared Imaging Method) images can be done in different ways. For example, a manual tripod or drone may be preferred. Care should be taken to ensure that the chosen method continues to meet the resolution requirements and that the method used is understood. Any known deviations or limitations shall be noted in the inspection report.
The inspection results verify the situation at the time of inspection. Problems of an intermittent or changing nature may or may not be captured during the inspection.
Thermographic Examination Visual Inspection
Prior to the thermographic inspection of solar power plants, a visual inspection is recommended to determine whether the requirements are met. Observations such as bird droppings, strong contamination, burn spots on modules or other balance-of-system components are to be documented with photos and locations prior to the thermographic inspection. These findings must be analysed before the thermographic examination, especially during commissioning. After resolution, photographs should be documented with pre-imaging. For a poorly performing solar power plant site, thermographic inspection may be requested without cleaning.
Upon observation of thermal abnormalities, it may be desirable to visually inspect the panels and visually observe any abnormal conditions in the area. A visual photograph will be taken for each thermal abnormality.
It is a limited examination to test the basic functioning of pv modules. Reliable conclusions on module quality are not possible, for example during system commissioning. Absolute temperatures are not determined, so thermal models are used to assess anomalies.
It is a detailed thermographic examination and analysis that may include thermal models. It can be useful for troubleshooting and periodic inspections. During this detailed measurement, absolute temperature measurements are determined. A competent specialist for PV power plants will have advanced qualifications together with thermographic experts.
What is Thermography?
Thermography is a non-contact, imaged temperature measurement method for finding and measuring thermal faults and recording temperature distributions. The invisible thermal radiation recorded by a detector is converted into a thermal image. Temperature distributions are analyzed by detecting overheated points on PV panels without affecting the measuring object. MapperX, an artificial intelligence technology software developed with image processing and machine learning techniques, automatically detects malfunctions of solar systems. You can review our article for detailed information about Automatic Fault Detection.
How Does Thermography Work?
The camera allows temperatures to be determined under real operating conditions. For the tester, this takes place at a safe distance from all hazardous parts of the system, without switching off the connected consumers, i.e. during ongoing operation. Infrared cameras create images of invisible infrared or thermal radiation. Since every technical component heats up before it fails, the recorded images show you possible irregularities at an early stage. Depending on the camera system used, this not only monitors the development of heat, but also detects and assesses the relative severity of heat-related problems.
- To reduce the risk of fire and accidents,
- Documentation of plant conditions and potential risks,
- Early detection of weak points or damage,
- Optimisation of plant availability and reliability,
- Prevention of collateral damage,
- Helps to reduce energy consumption, etc.