The novel evaluation method for PV module temperature and string size risk in utility-scale solar projects

Currently, utility-scale PV plants are increasing in number and power. Accurate estimation of PV module cell temperature is fundamental for PV project optimization. This article evaluates some of the most relevant models for PV module temperature estimation using real data from utility-scale projects, with different locations and current existing technology. For the assessment, a new weighting methodology is introduced to capture modeĺs behavior during critical periods for overvoltage episodes. The evaluation is based on error analysis, obtaining models’ accuracy against module’s real behavior in different utility-scale projects. The assessment of temperature error provides RMSE for direct error results between 0.25 and 1.45 °C for the evaluated 22 temperature cell models, confirming also which models provide a better temperature estimation during critical voltage periods. Once temperature models’ accuracy is obtained, their impact on open-circuit voltage and project́s risk is evaluated, leading to the introduction of a new model. This new model for string size risk evaluation, called “Grupotec String Evaluation” model, is developed, providing an innovative calculation method to obtain the probability of over-voltage episodes during the operation of PV projects. The Grupotec String Evaluation model is based on the model’s evaluation and project-specific data, which is considered a link between science and engineering to optimize generation from PV energy systems.