Wind Power Tower Research Articles

Research on damage identification of wind power tower structure based on deformation and vibration dual parameter analysis

Abstract During the operation of the wind turbine, the force on the wind turbine tower is mainly caused by the vibration source at the top. As a high-rise structure with a large span, traditional vibration mechanics is used to analyze the overall force on the tower body, but the analysis of vibration modes or modes is slightly insufficient. This article adopts the analysis method of elastic wave dynamics to identify damage to the structure of wind power towers based on deformation and vibration dual parameter analysis. This article analyzes the propagation characteristics of elastic waves in tower structures, concrete bases, and foundation parts when damaged. This article develops a remote online monitoring and early warning platform for wind power tower bodies based on the attenuation properties of elastic waves. This article monitors the vibration and inclination of the tower drums of 5 wind turbines (# 13, # 31, # 34, # 49, and # 52). The tower drums have not undergone irreversible tilting or torsional deformation. However, through vibration analysis, it is suggested to check whether there is crushing between the tower drums and the concrete base, as well as whether there are local cracks on the surface of the concrete base. There may be local damage to the foundation ring of tower #31. It is recommended to check for local cracks in the foundation ring. This ensures the safe operation of wind power towers and has certain practical application value.

An optimized single-side inverse finite element method for displacement field reconstruction of wind turbine tower

Wind turbines are subjected to complex dynamic loads during actual operation, which are difficult to predict accurately in advance, which may lead to inaccurate structural strength assessment in the structural design stage, and thus bring safety risks to wind power towers. Inverse Finite Element Method (iFEM) is a reconstruction method of structural displacement distribution, which can estimate the full-field displacement distribution of tower, and used for structural on-line health monitoring. However, conventional iFEM require sensors to be placed on both sides of the structure, which greatly limits its engineering practicality. For this reason, a single-side inverse finite element (iFEM_S) was developed in this study to enhance the engineering applicability of iFEM. Both iFEM and iFEM_S are based on the principle of least squares variation, and the solution equations can be established when the measured strain is known. The core idea of iFEM_S is to find the optimal node displacement s to minimize the sum of mean square errors between the theoretical and measured strains on one side of the structure, thereby generating a set of algebraic equations. Solving these linear equations can achieve the structural displacement field. Additionally, A cyclic optimization algorithm (COA) was developed in this study to improve the robustness of reconstruction results through optimizing strain gauge locations, in which the condition number of pseudo stiffness matrix was used as the objective function, and the condition number is minimized, named iFEM_S_O. Finally, the reconstruction accuracy and robustness and of iFEM, iFEM_S and iFEM_S_O were verified through several numerical examples. The simulated reconstruction results indicated that iFEM_S_O is more accurate and stable than iFEM_S, and iFEM_S is more accurate and stable than iFEM.

Real time detection of fatigue cracks on steel structures by applying square wave induction

For years the Eddy currents principle together with inductive thermography have been applied to detect cracks or defects in metallic machine components. In case a component has a crack, by inducing Eddy currents within a coil, it is possible to cause a temperature increase in the edges of the crack. This temperature variation can be observed by using an infrared camera. Thus, the crack is registered and observed in the infrared images, which are later analyzed. However, currently used systems require an enormous amount of power and a long time for image processing. For this reason, applying this method to large steel structures such as bridges, cranes, wind power towers, pipe lines or offshore oil stations has been much more complex. To overcome these limitations, a light portable system that optimally recreates the Eddy currents principle has been developed and used in this research. This system generates a square wave AC voltage, it uses considerably less power and it is capable of detecting cracks in real time. This paper presents the simulations and experiments carried out on two different structural steel specimens to demonstrate the efficiency of the system and its potential in the field of nondestructive testing.

Characteristics and Driving Mechanisms of Coastal Wind Speed during the Typhoon Season: A Case Study of Typhoon Lekima

The development and utilization of wind energy is of great significance to the sustainable development of China’s economy and the realization of the “dual carbon” goal. Under typhoon conditions, the randomness and volatility of wind speed significantly impact the energy efficiency and design of wind turbines. This paper analyzed the changes in wind speed and direction using the BFAST method and Hurst index based on data collected at 10 m, 30 m, 50 m, and 70 m heights from a wind power tower in Yancheng, Jiangsu Province. Furthermore, the paper examined the causes of wind speed and direction changes using wind speed near the typhoon center, distance from the typhoon center to the wind tower, topographic data, and mesoscale system wind direction data. The conclusions drawn are as follows: (i) Using the BEAST method, change points were identified at 10 m, 30 m, 50 m, and 70 m heights, with 5, 5, 6, and 6 change points respectively. The change points at 10 m, 30 m, and 50 m occurred around node 325, while the change time at 70 m was inconsistent with other heights. Hurst index results indicated stronger inconsistency at 70 m altitude compared to other altitudes. (ii) By analyzing the wind direction sequence at 10 m, 30 m, 50 m, and 70 m, it was found that the wind direction changes follow the sequence Southeast (SE)—East (E)—Southeast (SE)—Southwest (SW)—West (W)—Northwest (NW). Notably, the trend of wind direction at 70 m significantly differed from other altitudes during the wind speed strengthening and weakening stages. (iii) Wind speed at 10 m and 70 m altitudes responded differently to the distance from the typhoon center and the wind near the typhoon center. The correlation between wind speed and the distance to the typhoon center was stronger at 10 m than at 70 m. The surface type and the mesoscale system’s wind direction also influenced the wind speed and direction. This study provides methods and theoretical support for analyzing short-term wind speed changes during typhoons, offering reliable support for selecting wind power forecast indicators and designing wind turbines under extreme gale weather conditions.

Research on the welding process of Q355ND thick plate with narrow gap double wire submerged arc welding

Abstract Aiming at the problems of low welding efficiency and unstable quality of thick plates of marine equipment in offshore deep-water areas represented by offshore wind power, the high-efficiency welding process of narrow-gap double-wire submerged arc welding of 30 mm thick Q355ND low alloy high-strength steel plate was developed by selecting the suitable welding material and welding process parameters. The results show that the welded joint has a beautiful appearance, well-fused sides, and no defects. The structure of the heat-affected zone of the joint is mainly composed of pro eutectoid ferrite, acicular ferrite, bainite, and a small amount of pearlite. The center of the seam is composed of a large amount of massive ferrite and a small amount of bainite. The average tensile strength of the joint reaches 536.5 Mpa, and the average impact energy of the weld center at -20°C reaches 48.4 J. The average impact energy of the heat-affected zone reaches 164 J. All physical and chemical performance tests meet the standard requirements. The development of welding processes has important practical significance for improving production efficiency and product quality. It will be widely used to construct offshore wind power towers, offshore platform jackets, and other offshore deep-water engineering equipment.

Experimental database and analysis of in-plane seismic behaviour of double steel-plate composite walls for wind power tower

A double-steel-plate composite wall (DSCW) is composed of two steel plates, infilled concrete, and connectors. Because of their superior mechanical performance, DSCWs have been widely used in engineering, especially in the field of wind power tower. However, only a few studies have been conducted on the in-plane seismic performance of DSCWs. This study focused on the in-plane seismic performance of DSCWs, and a dataset of the in-plane flexural and shear behaviours of DSCWs including over 200 specimens from more than 30 studies was built. First, various structural configurations and mechanical response parameters were adjusted to the same standard. The same parameters studied by different scholars were extracted and analysed to obtain the general rules of the influence of these parameters on the hysteresis performance of DSCWs (forward analysis), such as the distance-to-thickness ratio, axial load ratio, shear span ratio, connector type, steel plate thickness, material strength, and partition number. Second, a backward analysis using the entire database was conducted on the factors influencing different mechanical response parameters, including the failure modes, yield displacement angle, ultimate displacement angle, ductility, and energy dissipation capacity. Finally, the accuracy of the shear capacity equations in the different codes was verified using shear failure specimens from a database to provide suggestions for engineering practice.

Structural Vibration Suppression of Wind Turbine Based on Dynamic Vibration Absorption

The vibration of wind turbine towers is a critical issue affecting the reliability and safety of wind turbines. Tuned mass dampers (TMD) have been widely used to reduce the vibration of structures. In this study, the finite element simulation method is used to investigate the tower structure’s response to vibration with and without TMD at different placement positions. The results show that under fluctuating wind loads, the vibration displacement and acceleration in the downwind surface of the tower are larger than those in the windward surface. After installing TMD, the damping effect of the wind power tower can be effectively improved. Under the condition that the total mass ratio is constant, the arrangement of placing a single TMD at the top of the tower is changed to a distributed arrangement at the top and the flange. The placement position of TMD affects the vibration reduction effect and the reliability of the tower structure. A distributed arrangement of TMD can improve the reliability of the tower structure and reduce the space occupied by a single TMD.

Some issues about the foundation design of wind power tower in actual conditions in Vietnam

The current design of wind power tower foundations in our country is relatively new, the design consultancies in the country do not have much experience and have not fully updated the system of standards and technical documentation in wind power project design. Moreover, a wind power project is a kind of construction that is both related to construction engineering and electrical project, and this is a type of construction with high investment costs. Therefore, the requirements are set very complicated for the design works. In this article, the authors would like to refer to "Some issues about the foundation design of wind power tower in actual conditions in Vietnam".

Research on stress performance of universally wrapped assembled joints of lattice wind power tower with concrete-filled steel tube

With the control parameters of the wall thickness of the ball table and the thickness of the pressure plate of the ball table, four universal wrapped assembled joint models were designed for the research of stress performance via static loading test. The failure mode of the joint, the axial force–displacement curve of the web member, the equivalent stress distribution of the ball table and the pressure plate of the ball table were analyzed, and the ABQAUS finite element software was used for the analysis of parameter expansion of the specimen. The research results show that the failure modes of universally wrapped assembled joints can be divided into the buckling failure of the ball table and the strength failure of the material. The wall thickness of the ball table is the key parameter affecting the failure mode of the joints, and the thickness of the pressure plate of the ball table is the crucial parameter influencing the ultimate bearing capacity of the joints. The maximum equivalent stress of the pressure plate and the ball table at compression zone for all the joints is occurred at the side squeezed by the bolt ball, and the growth rate of the equivalent stress for the ball table at compression zone is more uniform than that at tension zone. According to the finite element analysis results, when the wall thickness of the ball table is greater than 7 mm, the thickness of the pressure plate of the ball table is greater than 16 mm, the growth rate of the ultimate bearing capacity of the joint is significantly decreased, therefore, it is recommended to use the wall thickness of 7 mm and the pressure plate thickness of 16 mm in the actual design of the project.

Analytical Models of Concrete Fatigue: A State-of-the-Art Review

Fatigue failure phenomena of the concrete structures under long-term low amplitude loading have attracted more attention. Some structures, such as wind power towers, offshore platforms, and high-speed railways, may resist millions of cycles loading during their intended lives. Over the past century, analytical methods for concrete fatigue are emerging. It is concluded that models for the concrete fatigue calculation can fall into four categories: the empirical model relying on fatigue tests, fatigue crack growth model in fracture mechanics, fatigue damage evolution model based on damage mechanics and advanced machine learning model. In this paper, a detailed review of fatigue computing methodology for concrete is presented, and the characteristics of different types of fatigue models have been stated and discussed.

Economic nonlinear model predictive control of fatigue for a hybrid wind-battery generation system

An economic nonlinear model predictive controller (ENMPC) is formulated for a wind turbine-battery hybrid generation system. The controller aims to maximize the operational profit of the generator by balancing between generated wind power and turbine tower fatigue as well as battery cyclic fatigue. Other than the tower fore-aft fatigue, tower side-side fatigue is also considered to assess impact on overall economic performance. A moving horizon estimator (MHE) is formulated to provide meaningful initialization to the ENMPC in presence of plant model mismatch.The formulated controller utilizes the parametric online rainflow counting (PORFC) approach for direct cyclic fatigue cost minimization within ENMPC. The closed-loop simulation shows significantly higher profit compared to a realistic base-case scenario and relatively higher profit compared to another economic controller.

Wind Turbines Fault Classification Treatment Method

With the aim of solving the problems arising from the low efficiency and low accuracy of fault classification of wind power towers and turbine equipment (referred to as wind power systems for short) using artificial data analysis, this paper takes the operational data for wind power systems as the research object and proposes an improved K-means weighted dynamic clustering fault classification algorithm (DT clustering). First, historical and asymmetrical operational data from wind power systems were pre-processed to construct the data time series matrix and establish the fault classification model; second, the linear approximate constrained optimization algorithm and multiple regression algorithm were combined to build the model parameter optimization model. Finally, the comparative analysis of various algorithms showed the superiority of this algorithm, and the effectiveness of this model should be proved in practical applications.

Key Points and Requirements of Quality Control during the Production Process of Wind Power Tower Cylinder

Key Points and Requirements of Quality Control during the Production Process of Wind Power Tower Cylinder

Monitoring the blades of a wind turbine by using videogrammetry

Wind power is a reliable source of clean energy that is extensively used around the world. The blades of wind turbines are subject to a variety of mechanical stresses while they rotate and it is important to monitor their condition and diagnose problems to ensure their safe operation. Prevalent methods to this end are designed to be applied when the turbines are not operating. Moreover, current techniques to examine turbines are limited in that they can be used only to inspect defects on the surfaces of their blades. However, many faults in the blades of wind turbines are apparent only when they are operating, which makes it important to closely monitor the state of the blades as the turbine bears loads of varying magnitudes. Based on advanced videogrammetry, this study proposes a series of techniques to detect structural defects in the blades of turbines during their normal operation. Measurements of the global movement and local deformation in their operation, combined with inspections of the surface of the blades through an unmanned aerial vehicle, enable a complete inspection of the blades of the turbine as well as its systems of transmission, gear box, and wind power tower. The proposed method represents an important technical advancement that can help repair defects in wind turbines in a timely manner to reduce the cost of maintenance of wind power systems.

Failure mechanism and vibration control for tower tube of wind generator under extreme climate

The wind power tower is sensitive to wind loads with high aspect ratio. The failure characteristics and failure mechanism of the wind turbine tower structure are analyzed under the extreme climate conditions. Based on the principle of tuned mass damper theory, the suspension damper application in wind turbine tower structure is designed. The appropriate typhoon wind speed spectrum is selected. With the finite element software, the 3D model for tower structure is established and the control effect of the damper structure is analyzed. The maximum displacement and acceleration of the structure under extreme climatic conditions are greatly reduced after the suspension tuned mass damper being given. The efficiency of vibration reduction is 80.26% and 54% respectively. The results show that the response of displacement and acceleration for the damper are obviously decreased, which is beneficial to the safety of the tower structure under the extreme climate condition.

Section Design of 3MW Wind Turbine Tower Applied by GFRP DSCT Structure

In this study, cross-sections of GFRP DSCT (Glass Fiber Reinforced Polymer Double-Skinned Composite Tubular) column applicable to a 3 MW wind power tower were designed and performance evaluations of the designed sections were conducted. Forty sections, which satisfied the required axial load and bending moment, were designed according to the corresponding hollow ratio using the AutoDSCT program. Each section was analyzed using the CoWiTA program with consideration of the nonlinearity of the material, concrete confinement effect, and large displacement effect. Consequently, for a section with a diameter of 4.5 m, the requirement was satisfied when the hollow ratio was 70% to 85%, and for the diameters of 4.275 m, 4.05 m, and 3.825 m, sections with hollow ratios between 70% and 82%, 70% and 76%, and only 70%, respectively, satisfied the requirement respectively. Further, modularization was also carried out on the columns for convenience and ease of transport, and the performance of each section was verified by presenting sections of the module for each height.

Behavioral Evaluation of Modular ICH RC Columns through Quasi-Static Cyclic Tests

Owing to the recent expansion in sizes of wind turbines, the required height for the wind turbine tower is increasing. Therefore, new types of structures are needed to fulfill this requirement. In this study, a modular Internally Confined Hollow Reinforced Concrete (ICH RC) column was suggested for a wind power tower, and quasi-static test was performed to evaluate its bending performance. One single body specimen (SP-S) and two modular specimens (SP-MP, SP-MF) applying different connection methods were fabricated. The specimens were designed and manufactured while considering the numerical analysis and conditions of the testing laboratory. The test was conducted by controlling the displacement according to the drift ratio. The experimental results of moments, lateral loads, displacements, dissipation energy, ductility, etc. for each specimen were compared with those of numerical modeling. Consequently, plastic hinges were found at the bottom of the column and connection part for SP-S and modular specimens, respectively, which is due to the rigidity change at the connection of the modular specimens. Therefore, the result of energy dissipation was 40% higher in the case of the modular specimens than that of SP-S whereas the lateral force and moment in the case of the modular specimens were smaller than those of SP-S. In terms of displacement and energy ductility, modular specimens exhibited 50% higher results than those of SP-S. For the future work, it is necessary to enhance the performance of the connection part to apply the modular ICH RC structure to a wind turbine tower.

An Economic Model Predictive Control Approach for Wind Power Smoothing and Tower Load Mitigation

Abstract Wind power intermittency represents one of the major challenges facing the future growth of grid-connected wind energy projects. The integration of wind turbines and energy storage systems (ESS) provides a viable approach to mitigate the unfavorable impact on grid stability and power quality. In this study, an economic model predictive control (MPC) framework is presented for an integrated wind turbine and flywheel energy storage system (FESS). The control objective is to smooth wind power output and mitigate tower fatigue load. The optimal control problem within the model predictive control framework has been formulated as a convex optimal control problem with linear dynamics and convex constraints that can be solved globally. The performance of the proposed control algorithm is compared to that of a baseline wind turbine controller. The effect of the proposed control actions on the fatigue loads acting on the tower and blades is investigated. The simulation results, with various wind scenarios, showed the ability of the proposed control algorithm to achieve the aforementioned objectives in terms of smoothing output power and mitigating tower fatigue load with negligible effect on the wind energy harvested.

Analysis on the principle and performance Index of Tower climbing Robot

In this paper, aiming at the special application environment of wind power tower, this paper compares the existing domestic and international wall-climbing robot products, studies its structural characteristics, adsorption principle, etc., and then uses the knowledge of kinematics and dynamics to analyze its vertical climbing and steering motion. The performance requirements and structural design goals of the wind turbine tower climbing robot are proposed. Analyze and compare different combinations of solutions, and finally determine the use of the track magnetic adsorption design. The theoretical analysis of the vertical climbing and in-situ steering mechanics of the design scheme shows that the track length design of the crawler climbing robot should not be too long, and it will generate large resistance when steering, which is not conducive to steering. At the same time, the stability of the climbing robot climbing on the tower is theoretically calculated, and the number of required adsorption units is obtained.

수직축 풍력터빈 성능향상을 위한 풍력타워 최적설계에 관한 연구

수직축 풍력터빈 성능향상을 위한 풍력타워 최적설계에 관한 연구