Desarrollo de soluciones innovadoras para el aseguramiento de la calidad y mitigación de riesgos en módulos fotovoltaicos

Resumen

In a utility-scale photovoltaic (PV) project, the main investment is associated with the supply of photovoltaic modules. Hence the importance of rigorous and effective quality controls on them that contribute to the minimization of the technological risks associated with this component, which has a critical importance in the profitability of the project. This thesis focuses on quality controls of PV modules in utility-scale PV projects. For this, the following points have been developed: - Design and implementation of a global quality control program of PV modules for utility-scale PV projects. The program is presented and critically analysed. It covers from the previous phase of the manufacture of modules, where the manufacturer is selected, going through the inspections and tests during manufacturing process until the operation phase of the modules. The activities that should be carried out to ensure the quality of the PV modules are described in each phase are presented. This program includes an STC control procedure leading to very low uncertainties. A key aspect of the proposed procedure is the use of a set of PV reference modules, which are previously calibrated in the same independent laboratory, thus ensuring homogeneity on their calibration. Then, they are distributed among the PV module manufacturer and the further control laboratories (at the origin and on-site). This way, the cross-calibration uncertainty is strongly minimized. - Design, development and implementation of three mobile laboratories “PV Mobile Labs”. These laboratories have been designed to carry out the on-site quality control tests of photovoltaic modules according to IEC standards and in-house procedures. These tests are: visual inspections, electrical insulation, maximum power determination at standard test conditions (STC), performance at low irradiance, electroluminescence tests and indoor infrared thermography. The design of the mobile laboratories ensures the reliability of the results as if conducted in a conventional laboratory. The implementation of these mobile laboratories represents a before and after regarding quality control of PV modules worldwide. - In-deep analysis of the data obtained upon the implementation of a specific procedure to control the STC power in PV modules. This procedure was implemented on a supply of approximately 700,000 multicrystalline p-type silicon BSF technology PV modules made by a worldwide known manufacturer (Tier-1, Q4 2015). First, during the manufacturing process, the analysis of the STC power measurements of the whole supply carried out by the modules' manufacturer is included, where the quality of these measurements was evaluated through a comparative contrast study in an independent laboratory on a sample of 4,000 modules. In addition, the LID on 180 modules and the resistance to the PID in a sample of 125 modules were characterized and critically analysed. Secondly, during the operation phase, the analysis of the STC power after the first 2 years of operation of the modules in desert conditions was also included. These measurements were carried out on a sample of 2,000 modules making use of an accredited mobile laboratory. The overall results showed the effectiveness of the implementation of the aforementioned procedure, which is based on the use of a set of reference modules (primary standards) with common calibration origin. It proved to be an effective way of reducing uncertainties all along the quality control process. Otherwise, i.e., using PV reference modules with different calibration origin at different control steps would represent an uncertainty source strongly limiting the quantitative assessment of relatively small degradation effects like LID, PID and yearly degradation rates. The susceptibility to PID, as observed on the PID test (chamber method) specified in IEC TS 62804, was practically negligible and the average LID degradation after 20 kWh/m2 of exposition to the sun was 1.5%. The degradation rate in the second year of operation was 0.32% with respect to the initial degradation occurred during the whole first year. Finally, it should be noted that, these resulting statistics can serve as a state-of-art reference for PV modules quality control.