Use of thermal imaging cameras in photovoltaic systems

Photovoltaic systems should do their job for decades. Unfortunately, the aging process leads to various defects and even partial failures. Many of these defects can be traced back to the boom times of solar systems. Less qualified personnel on duty led to consequences that can still be felt today - from insufficient solar yields and processing errors to safety and fire risks. But a lightning strike can also cause defects. Thermal imaging cameras are used to detect irregularities quickly and easily. Thermal imaging cameras quickly locate thermal abnormalities so they can be resolved.

Inspection of a photovoltaic system

Photovoltaic systems are checked easily, quickly and efficiently using thermal imaging cameras. During operation, thermal irregularities are identified that indicate defects.

It is important that the solar system is in operation and converts solar energy, otherwise the individual modules will not heat up. The guide value is 50% of the nominal power.

Normal findings

Benign irregularities are called normal findings. There are white spots on the thermal imaging camera display. These are screw connections, basic structures of the system and also connection boxes (usually connected to the back of the system). Normal findings should be ignored in the analysis.

Hot spots and defects

Hot spots and defects are detected through the thermal imager's ability to sense temperature differences. A thermal sensitivity of 100 mK is sufficient for this. The thermal sensitivity describes the smallest temperature difference that can be perceived with the camera.

There will always be some minor thermal differences. However, as soon as larger differences are visible, deviations of 2 K, the said point should be examined more closely.

In the case of defects, the total resistance of the cell sometimes increases. The cells are placed in series to output a high voltage. As a result, the same current flows through all cells. In the defective cell, the increased resistance leads to heating, making the defect clearly visible on the thermal imaging camera.

Defects can also be caused by lightning. The bypass iodes are destroyed in the process. They are visible on the IR images due to strong heating.

Hot spots indicate hot spots in the silicon semiconductor. They become punctiform, in the "measles" pattern, visible on the thermal imaging camera.

Handling of the device

For the simple thermal requirement of an inspection of photovoltaic or solar modules, one can disregard the sometimes high range of functions of the thermal imaging cameras.

It is important that the emission coefficient is set on the thermal imaging camera and adapted to the object to be examined. This describes how much heat an object emits compared to a black body (idealized material that perfectly absorbs and reflects heat).

The FOV (field of view) plays an equally important role. It describes the section that a camera can record from its surroundings. Devices that have a small FOV are more suitable for small objects with large distances and vice versa.

Purchasing a thermal imaging camera

When buying a thermal imaging camera, make sure that you have a large field of view. This allows you to control large modules at close range. The camera also has to cover a high temperature range. In addition, a high sensor resolution is essential for testing photovoltaic and solar systems. In comparison to damaged insulation in the house, detail is required for the electronics - it should have a minimum resolution of 300 x 200 pixels.

  • Simple, practical health tool for measuring body temperature
  • Measurement accuracy less than 0.5 °C
  • High temperature detection function based on the average of the people tested
  • Minimized risk with a distance of 1.5 m maintained between the operator and the person tested
  • Quick setup in any environment thanks to the tripod insert
Datasheet
User Manual

  • exceptional 9-hour battery life with standard Ni-MH rechargeable batteries or alkaline batteries
  • connectivity with current clamps and environmental measurement products: all the necessary measurements simultaneously (current, influencing quantities, dew point for identifying areas at risk from mould, etc.)
  • voice annotations to record your comments directly on the image
  • the possibility of renaming the images and thermograms by site
  • recording and storage in memory of the configurations for each application
Datasheet
User Manual
User Manual

  • 2 LCD screens: current intensity and potential
  • Simultaneous display of the current intensity and the potential
  • Possibility of manual adjustment of the potential
  • Compact and simple to use
  • Analogue output compatible with Computer-Assisted Experimentation software
  • Maximum potential indicator
  • Switches for current range (µA/mA) and potential range (-mV/+mV)
  • 2 ranges: 2, µA and/or 2 mA
  • Plotting of current/potential graphs
  • Powered via the mains (delivered with 9 V power supply)
Datasheet
User Manual
User Manual

  • testo 890 thermal imager with FeverDetection feature for detecting elevated facial surface temperatures
  • Reliable: 640 x 480 pixel resolution and extremely good thermal sensitivity
  • Secure: Visual or acoustic alarm indicates individuals with elevated body surface temperatures
  • Flexible: Thanks to an HDMI interface for data transfer to an external screen, it can also be used in semi-stationary applications such as security checks
Datasheet
User Manual
User Manual

  • testo 890 professional thermal imager: resolution 640 × 480 pixels, upgradable to 1280 × 960 pixels with SuperResolution technology, thermal sensitivity < 40 mK
  • Super-telephoto lens with a 6.6° x 5° field of view for the accurate recording of extremely distant objects
  • Sequence capturing in the instrument a possible option, humidity calculation, SiteRecognition, panorama image assistant, JPEG storage function and other practical features
Datasheet
User Manual
User Manual

  • Image quality with IR resolution of 320 x 240 pixels (with testo SuperResolution technology 640 × 480 pixels)
  • Thermal sensitivity <0.04 °C
  • Full control: Manual focus and interchangeable lenses
  • Free analytical software for creating professional reports
  • Measurement site recognition and automatic image management
  • App for analysis and creating on-site measurement reports
Datasheet
User Manual
User Manual

  • Image quality with IR resolution of 240 x 180 pixels (with testo SuperResolution technology 480 × 360 pixels)
  • Thermal sensitivity of 0.08 °C
  • Recording and documentation of ambient conditions via radio probe (humidity/temperature probe or clamp meter)
  • Free analytical software for creating professional reports
  • Fast measurement with fixed focus
  • App for analysis and creating on-site measurement reports
Datasheet
User Manual

  • Image quality with IR resolution of 160 x 120 pixels (with testo SuperResolution technology 320 × 240 pixels)
  • Thermal sensitivity of 0.08 °C
  • Free analytical software for creating professional reports
  • Automatic detection of hot and cold spots
  • Thermal images can be saved as JPEGs
  • App for analysis and creating on-site measurement reports
Datasheet
User Manual

  • Image quality with IR resolution of 160 x 120 pixels (with testo SuperResolution technology 320 × 240 pixels)
  • Thermal sensitivity of 0.1 °C
  • Automatic detection of hot and cold spots
  • Free analytical software for creating professional reports
  • Fast measurement with fixed focus
  • Measuring accuracy of ±2 °C
Datasheet
User Manual

Testo 872 thermal imager, 320 x 240 pixels (SuperResolution technology 640 x 480 pixels), Bluetooth / WLAN, ± 2 ° C; ± 2% of reading, laser marker
• Highest image quality: IR resolution of 320 x 240 pixels thanks to Testo SuperResolution technology 640 x 480 pixels
• Precise measurement: thermal perception of 0.06 ° C.
• Smart and wireless: Use your mobile device with the free Testo thermography app and listen wirelessly to the measured values ​​from the testo 770-3 current probe and the testo 605i humidity measuring device
• Integrated laser marker - also seen exactly as a measuring point in the thermal image

SuperResolution technology 640 x 480 pixels
Field of view: 42 ° x 30 °
Bluetooth / WLAN
Complaints: ±2°C, ±2% of the measured value

Datasheet
User Manual
User Manual

bluetooth
80x80 pixels
with feveralarm 32/42 °C
range complete -20/380°C
accuracity: ±0.5

Datasheet
Bedienungsanleitung

Touchscreen thermal imager
with video and picture in picture function,
384x 288 pixels (thermal image),
Measuring range: -20 ... + 400 ° C,
manual focus

Datasheet
User Manual

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