Current Issue : April-June Volume : 2025 Issue Number : 2 Articles : 5 Articles
The wind turbine gearbox, used as a multiplier, is one of the main components directly related to a wind turbine’s efficiency and lifespan. Therefore, strict control of the gearbox and its manufacturing processes and even minor improvements in this component strongly and positively impact energy production/generation over time. Since only some papers in the literature analyze the mechanical aspect of wind turbines, focusing on some parts in depth, this paper fills the gap by offering an analysis of the gearbox component under the highest amount of stress, namely relating to the sun shaft, as well as a more holistic analysis of the main gear drives, its components, and the lubrification system. Thus, this work diagnoses the fracture mechanics of a 1600 kW gearbox to identify the main reason for the fracture and how the chain of events took place, leading to catastrophic failure. The diagnoses involved numerical simulation (finite element analysis—FEA) and further analysis of the lubrication system, bearings, planetary stage gears, helical stage gears, and the high-speed shaft. In conclusion, although the numerical simulation showed high contact stresses on the sun shaft teeth, the region with the unexpectedly nucleated crack was the tip of the tooth. The most likely factors that led to premature failure were the missed lubrication for the planetary bearings, a lack of cleanliness in regard to the raw materials of the gears (voids found), and problems with the sun shaft heat treatment. With the sun gear’s shaft, planet bearings, and planet gears broken into pieces, those small and large pieces dropped into the oil, between the gears, and into the tooth ring, causing the premature and catastrophic gearbox failure....
This paper presents a structural optimization technique based on precise heat transfer analysis for transformers. Mechanical and thermal stresses during operation are particularly critical in confined environments, such as within wind turbine generators. To optimize the transformer’s structure, the temperature distribution is first calculated using computational fluid dynamics (CFD) based on the finite volume method. Eddy current losses, necessary for thermal analysis, are determined through electromagnetic analysis. These CFD results are then used as input conditions for structural analysis. Finally, structural optimization is performed on critical areas, primarily the radiation fins and panels. All models are analyzed in 3D, and the simulation results are validated through comparison with experimental data. Consequently, the optimized design results were validated against simulations, exhibiting a maximum deviation of 4%. These findings confirm the success of the proposed transformer design optimization....
In this paper, the performance of a Dual-Stator Winding Synchronous Reluctance Generator (SynRG) suitability for off-grid wind power generation is analyzed. The rotor of the SynRG has a slitted-rotor core to improve selected vital performance parameters. The SynRG with a slitted-rotor core was modeled using a two-dimensional (2D) Finite Element Method (FEM) to study the electromagnetic performance of key parameters of interest. To validate the FEA results, a prototype of the SynRG with a slitted rotor was tested in the laboratory for no-load operation and load operation for unity, lagging, and leading power factors. To evaluate the capability of the SynRG with a slitted-rotor core to operate in a wind turbine environment, the machine was modeled and simulated in Matlab/Simulink (R2023a) for dynamic responses. The FEA results reveal that the SynRG with a slitted-rotor core, compared with the conventional SynRG with the same ratings and specifications, reduces the torque ripple by 24.51%, 29.72%, and 13.13% when feeding 8 A to a load with unity, lagging, and leading power factors, respectively. The FEA results also show that the induced voltage on no-load of the SynRG with a slitted-rotor core, compared with the conventional SynRG of the same ratings and specifications, increases by 10.77% when the auxiliary winding is fed by a capacitive excitation current of 6 A. Furthermore, the same results show that with a fixed excitation capacitive current of 6 A, the effect of armature reaction of the SynRG with a slitted-rotor core is demagnetizing when operating with load currents having a lagging power factor, and magnetizing when operating with load currents having unity and leading power factors. The same patterns have been observed in the experimental results for different excitation capacitance values. The Matlab/Simulink results show that the SynRG with a slitted-rotor core has a quicker dynamic response than the conventional SynRG. However, a well-designed pitch-control mechanism for the wind turbine is necessary to account for changes in wind speeds....
As a weak part of the concrete tower in wind turbines, the insufficient shear capacity of vertical joints can cause the local shear failure of the tower, reduce the overall bearing capacity and stability of the tower, and lead to safety issues. At present, the splicing of tower vertical joints mainly uses epoxy resin filling and arc bolt connections. However, sometimes the concrete near the vertical joints is damaged due to compression after applying pretension to the arc bolts, which will affect the bearing capacity and stability of the entire tower structure. If other interface processes are used for vertical joint splicing, the shear performance will be directly affected. Therefore, in order to study the influence of different interface processes on the shear performance of vertical joints in concrete tower tubes, four vertical joint specimens were designed for a pull-out test under shear load and the failure mode of the specimens and the shear capacity of the vertical joint interface were analyzed and studied. The results showed that with an increase in epoxy thickness and the application of an interface chiseling treatment, as well as injecting epoxy resin into the channels, the shear performance of vertical joints could be enhanced. Finally, based on existing research and standardized design methods, the shear capacity of vertical joints in wind turbine concrete towers was predicted, which showed that the existing design methods were not yet fully applicable to the shear capacity design of vertical joints in wind turbine concrete towers with different interface processes. Further research is needed to supplement and improve them....
Transmission towers are an important component of the electric system, and their tall structural characteristics make them susceptible to failure under strong winds. Therefore, it is crucial to enhance the wind resistance of the transmission tower structures. This paper uses the finite element method to investigate the influence of a fixture-type reinforcement device (FRD) on the load-bearing performance of the transmission tower structure and explores the effects of different numbers of fixture pairs on the reinforcement. Based on this, the paper further analyzes the stress characteristics and failure modes of a typical tower structure under wind loads in two directions and investigates the influence of different reinforcement lengths on the wind resistance performance of the tower structure. The research results indicate that the FRD can effectively improve the deformation mode and failure characteristics of steel components under axial load. At the same time, using the FRD can effectively reduce the deformation of tower structures under strong wind, and only reinforcing three angled steel components can reduce the tower top displacement by about 55% and more....
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