Condition monitoring system for solar power plants with radiometric and thermographic sensors embedded in unmanned aerial vehicles

•The aim of this article is to develop a new CMS to detect dust in PV panels.•The CMS is embedded in an unmanned aerial vehicle.•The CMS employs a radiometric sensor, and the results are validated by thermography.•The approach is based on the emissivity that is produced by the surface.•Several scenarios were conducted using real solar PV panels. The photovoltaic solar energy industry is expanding, and there is therefore a need to increase and improve its maintainability, operating costs, availability, reliability, safety, life cycle, etc. The aim of this article is to design, develop and check a new condition monitoring system to detect dust in solar photovoltaic panels. The condition monitoring system uses a radiometric sensor connected to an Arduino platform. This novel approach is based on emissivity analysis produced over a surface and characterized with a low emissivity value when dust appears. A thermographic camera is also employed to validate the results provided by the radiometric sensor. The system is designed to be embedded in an unmanned aerial vehicle. Radiometric data is sent and analysed, Internet of Things is employed, and thermograms are stored for further processing. Several scenarios with a real solar panel are used in the experiments, in which the angles and distances of the sensors and surface conditions are studied. An analysis of the radiometric sensor provides accuracy results, and the presence of dust is identified in all scenarios.