HOW DOES THERMOGRAPHY WORK?
For many years, thermography has been used to test solar modules for defects in the laboratory or during production. To regular cameras and the naked eye, these errors are hardly visible or not visible at all. In thermography, the smallest temperature differences can be measured using an infrared-sensitive camera. These temperature differences usually indicate defects or system errors, depending on their size and characteristics.
PV systems absorb part of the radiation emitted by the sun and generate electricity in this way. The non-absorbed part of the radiation is reflected.
The thermographic camera receives and measures the reflected radiation and translates it into temperatures. If a module is defective, it cannot absorb any radiation and thus reflects all the radiation – the thermal imaging camera measures this anomaly and records it.
The market for services concerning PV systems is very diverse. There are a multitude of possibilities to secure or improve the yields of solar installations, ranging from system monitoring to cleaning and complex test procedures.
However, many plant operators/owners ask themselves: Do I need a thermographic survey? And if so, which service is right for me? Thermography allows customers to precisely determine whether their system has defects, which modules are affected, and how to deal with this.
At the end of the day, the customer can quickly and easily recognise whether the system is performing as expected. Services and measures to remedy the defect can be taken.
Even for experienced solar asset management companies and O&M operations, thermography often offers surprising results. Thermographic imaging can reveal unexpected optimisation potential for performance ratios and cash flows for solar parks that were assumed to be performing optimally. Even the supposedly small defects, which could only be affecting an area of less than 1%, can result in a yield loss of more than 7%.
THE MOST COMMON ERRORS AND DEFECTS
Troubleshooting can take various forms. String failure can be caused by completely defective modules and/or an incorrect plug connection. In such a case, the modules either have to be replaced or the plug connection simply checked. The following is a list and explanations of more types of errors.
Production or transport errors, shades, or soiling can cause individual cells to heat up, resulting in performance losses.
Power loss: 2–10% of the module
One third of a module is idle and delivers no power. Usual cause: Defective bypass diode.
Power loss: 5–15% of the string
A single module is idle and delivers no power.
Power loss: 100% of the module
Planning errors or overgrown vegetation can lead to shades being cast on individual cells or entire modules and thus cause failure.
Power loss: depends on the individual case
A complete row of modules is idle and does not deliver any power.
Power loss: 100% for all affected modules
All connected modules are idle due to a faulty inverter.
Power loss: 100% of the inverter
(Potential Induced Degradation)
Fault pattern caused by potential differences at the negative pole of a module string, with considerable power losses.
up to 30% of the
module (differs between cases)
WHAT DO WE FLY WITH?
ucair selects pilots according to a specially created quality catalogue and takes case to use the most modern and safe technology. This applies to drones as well as to the cameras used. An excellent data foundation is the prerequisite for an excellent analysis.
THESE ARE THE BENEFITS
OF OUR DIGITAL
Your individual report creates added value:
- Recommendations for repairs
- Your local installer or O&M team can
perform targeted maintenance tasks
- Overview of all defects
- Proof needed to assert warranty claims with manufacturers