Analysis of the Frequency of Critical Failure Points in Photovoltaic Systems
Works Cited
Lorenzo, Gianfranco Di, et al. “Review of O&M Practices in PV Plants: Failures, Solutions, Remote Control, and Monitoring Tools.” IEEE Journal of Photovoltaics, vol. 10, no. 4, July 2020, pp. 914–926., https://doi.org/10.1109/jphotov.2020.2994531.
Annotation: This journal publication outlines a list of major failures associated with PV farms at large. This study focused on 80 solar farms in Italy. As a personal note, the geological location should be highly considered in studies like this. A list of common issues include geological instability, string fuses, overvoltages, overheating, inverters, DC insulation, MV/LV (medium/low voltage) transformers, and the modules themselves. A summary of number of these failures and repairs costs were provided, but the study itself states it could not confidently provide insight on potential lost revenue for the downtime. This could possibly considered in another study with better insight of cost estimate over time. The study does provide information about the monitoring of systems for failures and their associated cost. The monitoring section itself isn't entirely relevant, but an argument can be made for the importance of this research by reduction of cost from targeting critical failure points.
Manganiello, Patrizio, et al. “A Survey on Mismatching and Aging of PV Modules: The Closed Loop.” IEEE Transactions on Industrial Electronics, vol. 62, no. 11, Nov. 2015, pp. 7276–7286., https://doi.org/10.1109/tie.2015.2418731.
Annotation: This publication focuses primarily on the modules themselves and their frequent failure points. However, it does still briefly mention the most frequent failure points outside of the PV modules themselves. This study also appears to incorporate statistics over a handful of continents as opposed to one region, making the data that much more valuable. The PV module issues discussed include discoloration, delamination, bubbles, AR coating degradation, corrosion, cell cracking, ribbon and solder bond degradation, dust and soiling, potential induced degradation (PID), junction box and bypass diodes effects, localized heating, and frame detachment. The study goes on to define very specific information about environmental factors that cause many of these issue. Using that information, it's possible to deduce a list of 'best practices' for manufacturing and installation to extend the lifetime of PV farm components. The study also brings up an interesting point about mismatching, where some cells in a PV module operate worse than others, causing the entire module to suffer for it. I wonder if this phenomenon applies to arrays as well, and if more care should be taken for quality control if a single cell failing has such a profound effect.
R. Kaplar et al., "PV Inverter Performance and Reliability: What is the Role of the IGBT?," 2011 37th IEEE Photovoltaic Specialists Conference, Seattle, WA, USA, 2011, pp. 001842-001847, doi: 10.1109/PVSC.2011.6186311.
Annotation: This conference topic places the focus on the inverter in a PV system. The inverter is what converts the DC power from the panels into AC power, which can be transmitted over longer distances (i.e. the power grid). The study details manufacturing/quality control issues, design issues, and individual component failure in separate parts to analyze the problem. Specific issues include loose terminals and screws, broken wires, and loose connectors. IGBTs (insulated-gate bipolar transistors) were the primary focus, however, as they are essentially what make the inverter tick. They observed that many of the IGBTs tested operated fine under normal and extreme conditions, but some broke down even under normal operation, some to the point of total failure. They state more research is needed to examine behavior under extreme ambient conditions such as high temperatures and humidity. They don't seem to state any direct conclusions on why some failed and some didn't but considering some failed even under normal operating conditions, it could be believed that manufacturing quality control is poor, the heat generated from their constant, high frequency use accelerates degradation perhaps outside of normal operating conditions, or possibly both. I would have to analyze this entire study at length before making a formal hypothesis.
