Diagnosis of power losses in PV plants by means of UAV thermography

Abstract

This paper presents a technique to relate the temperature distribution over solar panel, achievable by means of the UAV thermography, with the electrical power distribution which is the cause of those temperatures. Differently from a mere thermal analysis, that can only identify “hotter” regions throughout the solar field, this technique allows evaluating electrical power losses associated to malfunctioning events. The method is based on the energy balance between the sun irradiance, which tends to heat up the solar cells, and the electrical behavior, which tends to cool down if the cell is converting light, while tends to further increase the cell temperature in those cases in which the cell behaves as a load. The reliability of the technique is evidenced by providing simulated thermal maps, achieved by means of known electrical and irradiance conditions, which are analyzed to re-achieve the starting electrical condition at the single cell level.