Quantitative assessment of the power loss of silicon PV modules by IR thermography and its dependence on data‐filtering criteria

Abstract

Reliability and quality control of photovoltaic (PV) plants increases in importance as the relevance of PV for the worldwide renewable energy production grows. In this study, a new method is presented which allows for a quantitative assessment of silicon PV module performance solely by relying on the cell temperatures measured via thermography (IR). A module temperature and power key figure are formulated and found to correlate very well with a linear relationship. The dependence of the deduced correlation's precision on measurement conditions is calculated and discussed. It facilitates decision‐making because optimal measurement conditions usually occur only very rarely, such that a compromise between data quality and measurement frequency has to be found. The power loss correlation presented in this paper may be used as part of a maintenance routine in order to ensure the best possible long‐term performance of the PV plant over its lifetime. The practical application in the field is outlined and explained.

Detecting Defects in Photovoltaic Cells and Panels With the Help of Time-Resolved Thermography Under Outdoor Environmental Conditions

“…Generally speaking, under indoor environmental conditions, it is possible to control the amount of light in the background and regulate the ambient temperature. However, under outdoor environmental conditions, as elaborated in [19], it is not possible to influence the given ambient conditions. That is why the impact of outdoor environmental conditions have to be examined and, if necessary, taken into account.…”

“…The reference temperature was taken from the measurement setup on which the DUT was placed. In contrast to other approaches such as [19], which require a reference sample, it is worth noting that for TRT a reference is not needed. Thus, the temperature was only taken as a reference to get an understanding whether the temperature differences observed in IR-images are caused by forward biasing the PV panel with the external power supply or by changes in the ambient conditions.…”

“…More precisely, IR-images obtained under outdoor environmental conditions show fewer or not all defects in PV panels in comparison to indoor measurements [18]. Similarly, Teubner et al [19] report that weather conditions can affect the results of IR thermography. In their work, for measurements outdoors, steady-sate conditions are preferred in which the solar radiation level does not change within a certain period of time [19].…”

Rapid Fault Diagnosis of Photovoltaic Panels Under Outdoor Environmental Conditions

“…Recently, experiments were carried out with IRT techniques also to detect defects in PV panels under outdoor environmental conditions [18]- [20]. However, under outdoor environmental conditions such as irradiation can influence IRT techniques in various ways and, thus, the obtained measurement results [19], [20].…”

“…IR-cameras can be equipped to unmanned aerial vehicles (UAVs) to carry out diagnosis on the condition of PV panels within a PV power plant. IR-cameras including weather stations to measure ambient temperature, wind speed, relative humidity, horizontal irradiation can also be used to monitor PV power plants on a continuous basis [19]. However, in order to minimise the efforts and costs for detecting defects in PV panels, a simple IRT technique is needed which is independent of environmental conditions.…”