| dc.description.abstract | Thermography is a temperature measurement technique with great potential for verifying the performance and physical integrity of photovoltaic panels, since it provides means for inspection at long distances and in a non-invasive way. However, the methodologies currently applied in thermographic inspections of photovoltaic panels in operation have a qualitative character. Procedures do not aim to determine the panel temperature, but to identify thermal abnormalities. This is mainly due to the difficulty in determining the temperature of the panels, which is dependent on environmental conditions, the physical properties of the panel and the measurement procedure adopted, such as the positioning of the camera e.g.. This work presents a methodology for thermographic evaluation of photovoltaic panels, based on a metrological analysis of the results. The thermographic panel inspections were carried out in the experimental photovoltaic power plant TESLA located at the School of Engineering of UFMG. The first proposed procedure was based on inspection of the mirrored surface of the panel. In this case, the results demonstrated that the main component of measurement uncertainty was the reflection. From the metrological point of view, the reflection was considered as a component of the uncertainty due to the emissivity (namely apparent emissivity), so that each inspection was characterized with a distinct value of apparent emissivity, between 0.1 and 0.65. This factor was responsible for between 78% and 95% of the measurement uncertainties in the mirror region of the cell. In order to mitigate the problem of measurement uncertainty due to reflection of mirrored surface, an inspection at the back-surface was proposed as alternative. Due to the characteristics of the material the measurements performed were more accurate, with measurement uncertainties below 2° C. | |
