| Work Detail |
New research in Morocco has found that Sandia’s PV panel performance model is best suited for measuring AC power in PV systems located in arid climate conditions. Scientists conducted a series of tests on three different PV systems located at a test center in Ben Guerir, central Morocco.
Researchers at Hassan II University (Morocco) have created a new methodology for the continuous monitoring of the durability and reliability of photovoltaic inverters in semi-arid climate scenarios, where the annual failure rate is considerable.
The proposed approach consists of comparing the measured power with the expected normal operating power of the photovoltaic systems.
Their analysis was carried out on three different south-facing PV systems, with capacities of 7.2 kW, 16.5 kW and 22.2 kW, at the Green Energy Park , a solar and renewable energy testing, research and innovation platform in Ben Guerir, central Morocco. The first system was based on copper indium gallium selenide (CIGS) modules, while the other two installations used unspecified monocrystalline PV module technologies, and all systems were connected to inverters monitored via a PV string monitoring unit.
The outdoor test facility uses a data acquisition system that records electrical parameters such as AC and DC power, current, voltage, and frequency, with data loggers interconnected to each system and a sampling time of two minutes. The study dataset includes data from January 2018 to August 2023.
For their evaluation, the researchers looked at three inverter models to identify which most accurately reflects the inverter’s measured AC output power: the Sandia PV Panel Performance Model developed by the U.S. Department of Energy’s Sandia National Laboratories; PVWatts, which is a popular web application for estimating the power output of a grid-connected photovoltaic (PV) system developed by the National Renewable Energy Laboratory (NREL); and Driesse, which was also developed at Sandia.
The analysis revealed that Sandia’s PV panel performance model showed the lowest root mean square error (RMSE), implying that the mean prediction errors were also lower, according to the researchers. “In addition, the Sandia model’s coefficient of determination (R2 ) was excessively high, approaching 1, indicating a robust correlation with the measured AC power,” they further explained. “Overall, this comparative analysis unambiguously shows that Sandia’s model outperforms the others in predicting PV inverter performance, with lower error measures and higher R2 values .”
Measurements also showed that over the 5-year period, the 7.2 kW, 16.5 kW and 22.2 kW systems had a weighted efficiency drop of 3.96%, 0.63% and 1.29%, respectively. “These findings have implications for comprehensive maintenance strategies, including periodic inspections, safety protocols and remote monitoring solutions,” the research group stated.
The proposed approach was presented in the study “ Assessing PV inverter efficiency degradation under semi-arid conditions: A case study in Morocco ”, which was recently published in Heliyon . “This research is more suitable for general failure analysis,” the academics concluded. “These approaches are worth exploring for detecting thermal stress, fouling, humidity, corrosion, electrical stress, and component ageing.” |
