Application of Infrared Thermography in an Adequate Reusability Analysis of Photovoltaic Modules Affected by Hail

Abstract

Infrared thermography, in the analysis of photovoltaic (PV) power plants, is a mature technical discipline. In the event of a hailstorm that leaves the PV system without the support of the power grid (and a significant portion of the generation potential), thermography is the easiest way to determine the condition of the modules and revive the existing system with the available resources. This paper presents research conducted on a 30 kW part of a 420 kW PV power plant, and demonstrates the procedure for inspecting visually correct modules that have suffered from a major natural disaster. The severity of the disaster is shown by the fact that only 14% of the PV modules at the test site remained intact. Following the recommendations of the standard IEC TS 62446-3, a thermographic analysis was performed. The thermographic analysis was preceded by an analysis of the I-V curve, which was presented in detail using two characteristic modules as examples. I-V curve measurements are necessary to relate the measured values of the radiation and the measured contact temperature of the module to the thermal patterns. The analysis concluded that soiled modules must be cleaned, regardless of the degree of soiling. The test results clearly indicated defective module elements that would result in a safety violation if reused. The research shows that the validity criterion defined on the basis of the analysis of the reference module can be supplemented, but can also be replaced by a statistical analysis of several modules. The comparison between the thermographic analysis and the visual inspection clearly confirmed thermography as a complementary method for testing PV-s.

Infrared imaging of photovoltaic modules: a review of the state of the art and future challenges facing gigawatt photovoltaic power stations

“…Furthermore, the image quality is of importance. Camera properties, as wavelength, pixels, instantaneous field of view (IFOV) determine the limits of the lateral resolution, addressed in [6,54,55]. View angle and altitude/distance [55][56][57] also need to be taken into account.…”

“…IR-images from polymer rear side of the PV-modules can be beneficial (rear-side IR-imaging, see figure 10 for an example), because of different emissivity and thermal properties of front side glass and rear side polymer. The emissivity in the infrared spectral range for glass surfaces is ε ≈ 85% [54,62,63] and for polymers ε ≈ 90%-93% [64,65]. Furthermore, the blurring is reduced due to thin polymer layers behind the solar cell (ca.…”

“…Because the emissivity of glass surface is ε ≈ 85% in the infrared spectral range [54,62,63], IR-images from the highly emitting polymer rear side of the PV-modules can be beneficial (rear-side IR-imaging, see figure 10 for an example).…”

Most Searched Topics in the Scientific Literature on Failures in Photovoltaic Installations

“…hailstorms, which can damage the panes of glass in the panels [26,27], -the heavy or frequent cloudiness [28], -poor solar irradiance [29], -strong winds [30], -fire in the installation caused by lightning [22,25].…”