scholarly journals Field Monitoring and Numerical Analysis of the Reinforced Concrete Foundation of a Large-Scale Wind Turbine

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Yanming Zhou ◽  
Xinxi Liu ◽  
Zongwei Deng ◽  
Qian-Feng Gao
Keyword(s):  
Reinforced Concrete ◽  
Wind Turbine ◽  
Large Scale ◽  
Dynamic Contact ◽  
Shallow Foundation ◽  
Foundation Design ◽  
Onshore Wind ◽  
Concrete Foundation ◽  
Operation Phase ◽  
Contact Pressures

The objective of this study is to examine the performance of the shallow reinforced concrete foundation of a large-scale wind turbine under the influence of environmental loads. A 2 MW horizontal-axis onshore wind turbine supported by a shallow concrete foundation was considered. The foundation stresses, foundation settlements, and static and dynamic contact pressures at various positions of the shallow foundation were monitored from the construction phase to the operation phase in the field. Numerical simulations were also performed to further analyze the behavior of the wind turbine foundation in different cases. The results demonstrate that the responses of the reinforced concrete foundation, i.e., foundation stresses, contact pressures, and foundation settlements, were variables closely related to the wind direction and wind speed. The distribution of foundation stresses suggested that a reasonable design of steel reinforcement cages around the foundation steel ring is important. The dynamic contact pressure of the foundation could reach 5 kPa, so the influence of dynamic wind loads on the foundation response could not be always neglected, particularly for the foundations seated on weak soils. The foundation settlement during the operation phase could be characterized by the logistic model, but its distribution was uneven due to the presence of eccentric upper weight and wind load. The findings would provide guidance for the foundation design of onshore wind turbines in hilly areas.

OPTIMUM DESIGN OF REINFORCED CONCRETE FOUNDATIONS

2020 ◽  
Vol 14 ◽  
Author(s):  
Osama Bedair
Keyword(s):  
Reinforced Concrete ◽  
Cost Function ◽  
Numerical Procedure ◽  
Optimization Procedure ◽  
Analytical Models ◽  
Design Parameters ◽  
Foundation Design ◽  
Programming Technique ◽  
Concrete Foundation ◽  
The Cost

Background: Optimization of reinforced concrete foundation is a challenging problem in practice due to interaction between the design variables and constraints. Classical design methods may overestimate the size of the foundation, thus leading to excessive cost. By using current advances in computer technologies and numerical optimization procedures, it is possible to find the optimum combinations of foundations design parameters that minimize the cost. Objectives: The paper presents a numerical strategy to optimize the design of reinforced concrete foundation. Method: The cost function is first derived in terms of the foundation design parameters. Mathematical programming technique is utilized to minimize the cost function. Design constraints are used against soil bearing capacity, concrete shear strength, flexural strength and column bearing. Simplified analytical models are developed to idealize the soil stress distribution. The numerical procedure is then automated in a computer Program “OSFD” to perform sensitivity analysis and provide guidelines that can be utilized in practice. Results: Design examples are provided to illustrate efficiency of the optimization procedure. Results are compared with exiting conventional design procedures, commercial softwares and design handbooks available in practice. Conclusions: The described procedure is very cost effective that can be effectively utilized by practicing Engineers in the industry to optimize the design of reinforced concrete foundation.

Dynamic responses of the shallow foundation of an onshore wind turbine

2019 ◽  
Vol 19 (5) ◽  
pp. 247-260
Author(s):  
Zong-Wei Deng ◽  
Qian-Feng Gao ◽  
Hui Dong ◽  
Liu-Xi Li
Keyword(s):  
Wind Turbine ◽  
Shallow Foundation ◽  
Dynamic Responses ◽  
Onshore Wind

scholarly journals Capacity of Cone-Shaped Hollow Flexible Reinforced Concrete Foundation (CHFRF) in Sand under Horizontal Loading

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Shanshan Li ◽  
Yukun Zhang ◽  
Dayong Li
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Bearing Capacity ◽  
Wind Turbine ◽  
Earth Pressure ◽  
Ultimate State ◽  
Foundation Pit ◽  
Rubber Layer ◽  
Concrete Foundation ◽  
The Earth

The cone-shaped hollow flexible reinforced concrete foundation (CHFRF) is an innovative type of mountain wind turbine foundation, which outperforms the regular mountain wind turbine foundation in reducing the steel and concrete and protecting the surrounding vegetation for the cavity absorbs soil obtained from excavating the foundation pit. Moreover, the rubber layer installed between the wall of CHFRF and the surrounding ground increases foundation flexibility and releases the larger overturning moment induced by wind. The rubber layer is made of alternately laminated rubber and steel. The objectives of this research are to study the lateral bearing behaviors of the CHFRF under monotonic and cyclic lateral loading in sand by model tests and FEM simulations. The results reveal that the CHFRF rotates during loading; and, in the ultimate state, the rotation center is located at a depth of approximately 0.6–0.65 times the foundation height and is 0.15–0.18 times the diameter of the foundation away from its centerline as well. The lateral bearing capacity of the CHFRF improves with the increase of embedded depth and vertical load applied to the foundation. Moreover, compared to the CHFRF without the rubber layer, the rubber layer can reduce the earth pressure along the wall of CHFRF by 22% and decrease the deformed range of the soil surrounding the foundation, revealing that it can reduce the loads transferred to the surrounding soil for extending the service life of the foundation. However, the thickness and stiffness of the rubber layer are important factors influencing the lateral bearing capacity and the energy dissipation of the foundation. Moreover, it should be noted that the energy dissipation mainly comes from the steel of the rubber layer rather than rubber.

Aerodynamic Rotor Performance of a 3300-kW Modern Commercial Large-Scale Wind Turbine Installed in a Wind Farm

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Mehmet Bilgili ◽  
Mehmet Tontu ◽  
Besir Sahin
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Large Scale ◽  
Wind Farm ◽  
Thrust Force ◽  
Speed Ratio ◽  
Flow Angle ◽  
Onshore Wind ◽  
Turbine Performance

Abstract Wind turbine technology in the world has been developed by continuously improving turbine performance, design, and efficiency. Over the last 40 years, the rated capacity and dimension of the commercial wind turbines have increased dramatically, so the energy cost has declined significantly, and the industry has moved from an idealistic position to an acknowledged component of the power generation industry. For this reason, a thorough examination of the aerodynamic rotor performance of a modern large-scale wind turbine working on existing onshore wind farms is critically important to monitor and control the turbine performance and also for forecasting turbine power. This study focuses on the aerodynamic rotor performance of a 3300-kW modern commercial large-scale wind turbine operating on an existing onshore wind farm based on the measurement data. First, frequency distributions of wind speeds and directions were obtained using measurements over one year. Then, wind turbine parameters such as free-stream wind speed (U∞), far wake wind speed (UW), axial flow induction factor (a), wind turbine power coefficient (CP), tangential flow induction factor (a′), thrust force coefficient (CT), thrust force (T), tip-speed ratio (λ), and flow angle (ϕ) were calculated using the measured rotor disc wind speed (UD), atmospheric air temperature (Tatm), turbine rotational speed (Ω), and turbine power output (P) parameters. According to the results obtained, the maximum P, CP, CT, T, and Ω were calculated as approximately 3.3 MW, 0.45, 0.6, 330 kN, and 12.9 rpm, respectively, while the optimum λ, ϕ, U∞, and Ω for the maximum CP were determined as 7.5–8.5, 6–6.3°, 5–10 m/s, and 6–10 rpm, respectively. These calculated results can contribute to assessing the economic and technical feasibility of modern commercial large-scale wind turbines and supporting future developments in wind energy and turbine technology.

Overview of Subsynchronous Oscillation in Grid-connected Wind Farm

2020 ◽  
Vol 13 (7) ◽  
pp. 969-979
Author(s):  
Xu Pei-Zhen ◽  
Lu Yong-Geng ◽  
Cao Xi-Min
Keyword(s):  
Power Systems ◽  
Wind Turbine ◽  
Large Scale ◽  
Wind Farm ◽  
Wind Farms ◽  
Induction Generator ◽  
Future Research ◽  
Stable Operation ◽  
Subsynchronous Oscillation ◽  
Different Types

Background: Over the past few years, the subsynchronous oscillation (SSO) caused by the grid-connected wind farm had a bad influence on the stable operation of the system and has now become a bottleneck factor restricting the efficient utilization of wind power. How to mitigate and suppress the phenomenon of SSO of wind farms has become the focus of power system research. Methods: This paper first analyzes the SSO of different types of wind turbines, including squirrelcage induction generator based wind turbine (SCIG-WT), permanent magnet synchronous generator- based wind turbine (PMSG-WT), and doubly-fed induction generator based wind turbine (DFIG-WT). Then, the mechanisms of different types of SSO are proposed with the aim to better understand SSO in large-scale wind integrated power systems, and the main analytical methods suitable for studying the SSO of wind farms are summarized. Results: On the basis of results, using additional damping control suppression methods to solve SSO caused by the flexible power transmission devices and the wind turbine converter is recommended. Conclusion: The current development direction of the SSO of large-scale wind farm grid-connected systems is summarized and the current challenges and recommendations for future research and development are discussed.

scholarly journals Research on Zero-Voltage Ride Through Control Strategy of Doubly Fed Wind Turbine

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2287
Author(s):  
Kaina Qin ◽  
Shanshan Wang ◽  
Zhongjian Kang
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Control Strategy ◽  
Large Scale ◽  
Sliding Mode ◽  
Stable Operation ◽  
Wide Range ◽  
Dc Bus ◽  
Doubly Fed ◽  
Zero Voltage

With the rapid increase in the proportion of the installed wind power capacity in the total grid capacity, the state has put forward higher and higher requirements for wind power integration into the grid, among which the most difficult requirement is the zero-voltage ride through (ZVRT) capability of the wind turbine. When the voltage drops deeply, a series of transient processes, such as serious overvoltage, overcurrent, or speed rise, will occur in the motor, which will seriously endanger the safe operation of the wind turbine itself and its control system, and cause large-scale off-grid accident of wind generator. Therefore, it is of great significance to improve the uninterrupted operation ability of the wind turbine. Doubly fed induction generator (DFIG) can achieve the best wind energy tracking control in a wide range of wind speed and has the advantage of flexible power regulation. It is widely used at present, but it is sensitive to the grid voltage. In the current study, the DFIG is taken as the research object. The transient process of the DFIG during a fault is analyzed in detail. The mechanism of the rotor overcurrent and DC bus overvoltage of the DFIG during fault is studied. Additionally, the simulation model is built in DIgSILENT. The active crowbar hardware protection circuit is put into the rotor side of the wind turbine, and the extended state observer and terminal sliding mode control are added to the grid side converter control. Through the cooperative control technology, the rotor overcurrent and DC bus overvoltage can be suppressed to realize the zero-voltage ride-through of the doubly fed wind turbine, and ensure the safe and stable operation of the wind farm. Finally, the simulation results are presented to verify the theoretical analysis and the proposed control strategy.

Sign in / Sign up

Export Citation Format

Share Document