One of the key PV technology developments in 2021 is the emergence and deployment of large-format and high-powered modules. With claims that such modules provide improved Levelized Cost of Energy (LCoE) and deliver lower Balance of System (BOS) costs, there are many advantages to be reaped. Trina Solar examines the challenge for trackers.
New products bring new challenges, and the design of power plants is no exception. This is one area of focus for Trina Solar, a global provider of PV modules and smart energy solutions. The company has already launched a series of large-format modules, the Trina Solar Vertex 670, which achieves a 34% higher energy output than the average 500W+ modules.
Recognizing that PV tracker stability is a challenge for larger format modules, TrinaTracker, the tracker business unit of Trina Solar, has designed a new tracker series: the Agile 1P and Vanguard 2P. They are fully compatible with all ultra-high-power modules ranging from 400 to 670W, plus they provide optimized output even under extreme weather conditions.
Wind tunnel testing
The test to validate tracker stability involved using a reproduction of Vanguard 2P and Agile lP scale prototypes and subjected to static, aeroelastic, and dynamic loads via wind tunnel tests performed by wind engineering consultancy firms CPP and RWDI.
The tests comprised Pressure Model Wind Tunnel Research, 2D Sectional Model Test & Numerical Models, and an additional Full Aeroelastic Model Test. The third model corroborated the output obtained from the 2 Sectional Model Test and Numerical Models, tests not typically implemented in the industry.
The Pressure Model made it possible to obtain a more accurate definition of the static coefficients for different distances between rows, ground clearance, post separation or tracker length. Then, by adding data obtained from the Modal Analysis (natural frequencies) and the Free Vibration test (damping ratios), the DAF (Dynamic Amplification Factor) was attained.
The 2D Sectional Model enabled Aerodynamic Stability Analysis and Buffeting Response Analysis to be carried out using Numerical Models. The advantage of the data gained from the 2D sectional model is that the results were applied to a wide range of tracker dimensions.
The Numerical Models’ output was verified by comparing the results in the numerical model and the results in the full aeroelastic wind tunnel test. The wind tunnel tests evaluated the reactions of the main structural elements (posts, torque tube and purlin) and connecting components (bearings and drives) to the wind loads.
Deploying the results
With the analysis generated from the wind tunnel test results, the company determined the wind loads of the main structural elements (posts, torque tube and purlin) and connecting components (bearings and drives). It provided the output to upgrade the tracker designs and achieve more accurate adaptability to the sites. SBP ratified the calculation procedures that TrinaTracker adopted, with the output gathered from the wind tunnel tests.
Upon these tests, the tracker series was optimized to ensure the reliability and adaptability of all the system components. The designs were reviewed and included more robust posts, purlins that add rigidity to the modules, stiffer torque tube, different stow strategies for 1P and 2P configurations, tailored tracker layout, and multi-drive systems.
SBP ratified the calculation procedures that TrinaTracker adopted, with the output gathered from the wind tunnel tests.
Markus Balz, Managing Director of SBP, stated: “After several years of supporting tracker companies, EPCs and developers in the field of trackers, it is a relief to see TrinaTracker offering sophisticated design approaches to tackle safety and cost optimization at the same time.”
To get more exclusive information about the tests and how TrinaTracker ensures the tracker stability in extreme weather conditions, watch the webinar with experts taking you through the key test elements and results. You can also download the new whitepaper “Strategies to mitigate wind-related risks in trackers compatible with ultra-high-power modules” at: https://bit.ly/36RSXSI.