Drone inspection is an inspection method that is regularly used. The advantage is that a few megawatts of solar power system can be screened in a relatively short period of time without dismantling the modules. Thermographic inspection is the most common method. By means of temperature differences in the modules (see pictures below) possible defects can be detected and the modules can be replaced if necessary.

Then there is the possibility to have drone EL make images of the system. This is a high-end technique that makes EL images of each individual module in order to be able to inspect the general quality of the system with regard to micro-cracks and possibly which modules need to be replaced.

 

Advantages and disadvantages
Thermographic inspection is a fairly cost-efficient method for screening a solar power system at any location. It can serve as a good basis for determining whether more thorough inspection is necessary. The disadvantage of thermographic inspection is that it does not provide complete certainty that the defects found may influence the energy production of a series of panels. In addition, the weather conditions for performing reliable thermographic inspections are quite specific and occur on average about 50 days per year in the Netherlands. We therefore advise you to issue an order in time so that our operators can come directly to the site when the weather permits. Drone EL images are the best method to get a good picture of the solar panels in terms of possible damage from micro cracks. However, it is also a costly technique that must be performed during night time hours. This means that this technique can be used all year round, provided that the weather conditions such as wind and precipitation permit.

Drone flights in “restricted areas”
Everywhere in Europe there is a chance that the solar park is located in an area where flight restrictions apply, so-called CTR zones or restricted areas. Due to changed European regulations, we are in the process of obtaining all necessary certificates to be able to fly in these zones anywhere in Europe. However, in some countries (including NL) this may mean that we must then deploy an observer and apply for an exemption from the flight restrictions. This can mean additional costs. The costs of the exemption (read permit) differ per municipality.

The weather conditions (solar radiation and wind) determine the speed at which we can carry out the drone flight. In our report you will find how many days we have been busy. It may also be the case that the days have to be divided over more than 1 week, also this because of the weather conditions.

Drone and Camera
SolarTester works with a unique combination of drone and camera. Our camera in particular is the most advanced at the moment for application in our field. The Zenmuse XT2 640. This is a combination camera which can produce thermo and normal images. A camera with which we can simultaneously shoot both types of images instead of two separate cameras with which you then also have to fly separately over the system. This saves time and therefore costs for our client. We get high quality images where the regular image is identical to the modules captured by the thermo lens because the two cameras are integrated. In this way we can detect bad modules even better and in a targeted manner. Thanks to the radiometry in the camera, we can thoroughly analyse the thermo images of the modules in the office after filming.