FAST.Farm is a mid‐fidelity engineering tool developed by the National Renewable Energy Laboratory targeted at accurately and efficiently predicting wind turbine power production and structural loading in wind farm settings, including wake interactions between turbines. FAST.Farm is based on several principles of the dynamic wake meandering (DWM) model, but also addresses limitations of previous DWM

Wind turbine wakes negatively affect downwind turbines in wind farms reducing their global efficiency. The reduction of wake‐turbine interactions by actuating control on yaw angles and induction factors is an active area of research. In this study, the capability of spanwise‐periodic rows of wind turbines with tilted rotors to reduce negative wake‐turbine interactions is investigated through large‐eddy

When discussing the connection of wind energy and climate change, normally, the potential of wind energy to reduce green house gas emissions is emphasised. Hence, effects of wind energy on climate change are analysed. However, what about the other direction? What is the impact of climate change on wind energy? Recently, the effect of a reversal in global terrestrial stilling,that is, an increase in

Recent research developments have indicated that substantial reduction of both the fatigue and ultimate loads can be achieved by adopting trailing edge (TE) flap control strategies. Their aeroelastic tools employ blade element momentum (BEM) aerodynamic models enhanced with a sectional 2D treatment of the TE flap, neglecting the 3D effect of the trailed vorticity in the vicinity of the moving flap

As the global demand for clean renewable energy has grown, the contribution of wind power in grid systems has significantly improved. Wind power predictions play an important role in the stable and safe operation of grid systems. Considering the shortcomings of traditional wind power point predictions, a novel two‐stage short‐term wind power interval prediction method is proposed in this study. In

In this paper, we present a mathematical model and control strategy to regulate the yaw of a horizontal axis wind turbine. In order to obtain the dynamic equations of the yaw motion, the mathematical model is developed using the Euler–Lagrange formulation and considers the wind turbine as a manipulator robot with three degrees of freedom (DOF). A fuzzy proportional‐integral‐derivative (PID) controller

Three‐dimensional (3‐D) finite element models of structural (scarf) repair of wind turbine blade, including the composite patch, adhesive, coating and parent composite structures is developed. Computational studies of the effect of the scarf angle, thickness of the adhesive layer and the availability of voids in the adhesive on the stress field in the repaired structure were carried out. It is observed

Reducing downtime through predictive or condition‐based maintenance is a promising strategy to help reduce costs associated with wind farm operation and maintenance. To help effectively monitor wind turbine condition, operators now rely on multiply sources of data to make informed operational decisions which can minimise downtime, increasing availability and profitability of any given site. Two of

As a clean and renewable energy source, wind energy has achieved remarkable growth around the world. Wind power/speed interval prediction has become an indispensable area of focus regarding the efficient dispatch of wind energy. As an important interval prediction method, the traditional lower and upper bound estimation (LUBE) has been a prevalent approach and a fundamental branch of energy prediction

No abstract is available for this article.

The implementation of a model to simulate distributed surface roughness, which is the new k−ω extension by Knopp et al. into the DTU Wind Energy in‐house CFD Reynolds‐Average Naviar Stokes solver EllipSys, was validated against wind tunnel experiments conducted in the Laminar Wind Tunnel of the Institute of Aerodynamics and Gas Dynamics, University of Stuttgart. The effort was to predict the aerodynamic

This paper presents a modified S‐transform (ST) based on a compactly supported kernel. A version of Cheriet‐Belochrani (CB) kernel is chosen for this purpose. It is shown that the proposed modified S‐transform (CBST) offers better frequency resolution than the traditional ST. It is used to decompose the wind speed time series into frequency‐based subseries. Further, artificial neural network (ANN)

A 105‐m, 13‐MW two‐bladed downwind Segmented Ultralight Morphing Rotor (SUMR‐13) blade was gravo‐aeroelastically scaled by 20% to a 20.87‐m‐long demonstrator blade and confirmed through structural ground testing. The subscale model was achieved through geometric scaling and by aeroelastic scaling principles based on operational flapwise deflections combined with rotational and structural frequencies

Wind turbines play a crucial role in the revolution towards renewable resources. They need to be economically competitive to be sustainable. This still requires to lower the cost of energy (COE). To this end, nonlinear model predictive control (NMPC) is used within this paper. As known from literature, NMPC significantly improves the energy extracting performance as well as the mitigation of tower

The recovery of offshore wind farm wakes in the German Bight was analyzed by a unique in situ data set, measured on‐board the research aircraft Dornier Do‐128 during the WIPAFF project in 2016 and 2017. These observations were used to validate a simple analytical wake recovery model in five case studies. The observed recovery rates were compared with the results of the mesoscale Weather Research and

Predicting the occurrence of strong and sudden variations in wind power, so‐called ramp events, has become one of the main challenges for the operation of power systems with large shares of wind power. In this paper, we investigate 14 ramp events of different magnitudes and minute‐scale durations observed by a dual‐Doppler radar system at the Westermost Rough offshore wind farm. The identified ramps

Structural compactness with multiple meshing points excites multiple vibrations in a planetary gearbox of a wind turbine operating at varying speeds. The nonstationary, multicomponent vibration signals result in complex modulations challenging the effectiveness of a signal processing technique‐based fault diagnosis method. This paper aims to detect gear tooth faults under varying speed conditions based

In India, there are plans for 5 GW of installed capacity of wind power by 2022. This study establishes that the wind resource along the west coast of Gujarat is sufficient for offshore wind farms of between 500 MW to 2 GW rated power to be operated with capacity factors of 40% to 54%. For the majority of sites, a levelized cost of energy (LCOE) in the range 68 to 86 £/MWh can be achieved with installation

No abstract is available for this article.

In order to meet the increasing demand of wind energy utilization, wind turbines (WTs) are developing toward the trend of large size and large capacity. In such a trend, various advanced yaw control strategies have been proposed to improve large WTs' comprehensive performance, but the analysis and summary of these strategies are still lacking. Therefore, it is necessary to have a review of yaw control

Load alleviation control is highly desirable to reduce penalties associated with the added structural mass required to withstand rare load scenarios. This is particularly true for wind turbine designs incorporating long‐span blades. Implementation of compliance‐based morphing structures to modify the lift distribution passively has the potential to mitigate the impact of rare, but integrally threatening

As the worlds first floating wind farm, one of the main technical challenges in the design phase of Hywind Scotland was the uncertainty related to wake interaction effects between the floating wind turbines. In this paper, we address this challenge by presenting an analysis of full‐scale measurements from the Hywind Scotland wind farm. Measurements of the floaters' roll, pitch and yaw motions are presented

In the high pressure wind tunnel (HochDruckkanal Goettingen [HDG]) of Deutsch–Niederländische Windkanäle—German–Dutch Wind Tunnels (DNW) a 47% thick airfoil‐like symmetrical profile was investigated at a high (3 to 12 million) Reynolds number. As an unusual feature, a negative lift slope dcL/dα < 0 close to zero lift has been re‐observed under specific circumstances. We describe the findings and offer

This paper describes a nonlinear model inversion for performance analysis and system optimization for airborne wind energy (AWE) systems. Airborne wind energy systems are lighter and potentially lower in cost than comparable conventional wind turbines due to using a tether and bridle rather than blades and a tower which must support high bending and compressive loads. They are also easier to install

Because wind has a high volatility and the respective energy produced cannot be stored on a large scale because of excessive costs, it is of utmost importance to be able to forecast wind power generation with the highest accuracy possible. The aim of this paper is to compare 1‐h‐ahead wind power forecasts performance using artificial intelligence‐based methods, such as artificial neural networks (ANNs)

In this paper, a low computational, robust nonlinear feedback control is proposed as independent distributed generation controller (IDGC) for doubly fed induction generator (DFIG) based wind power generation system (WPGS). WPGS integration as distributed generation (DG) to grid point of common coupling (PCC) is reflecting high power loss profile in terms of low frequency oscillations under grid operational

The reduction of structural loads is becoming an important objective for the wind turbine control system due to the ever‐increasing specifications/demands on wind turbine rated power and related growth of turbine dimensions. Among various control algorithms that have been researched in recent years, the individual pitch control has demonstrated its effectiveness in wind turbine load reduction. Since

For wind turbine blades with the increased slenderness ratio, flutter instability may occur at lower wind and rotational speeds. For long blades, at the flutter condition, relative velocities at blade sections away from the hub center are usually in the subsonic compressible range. In this study, for the first time for composite wind turbine blades, a frequency domain classical flutter analysis methodology

This paper investigates the characteristics of turbine wake which is the major factor determining the turbulence in wind farm and overall wind farm performance. Using the lattice Boltzmann method (LBM) and the large eddy simulation (LES) approach, dynamic simulations of detailed fluid flow and wake trajectory induced by the MEXICO wind turbine were carried out. Moreover, with the help of adaptive mesh

In the near future, wind and solar generation are projected to play an increasingly important role in Europe's energy sector. With such fast‐growing renewable energy development, the presence of simultaneous calm wind and overcast conditions could cause significant shortfalls in production with potentially serious consequences for system operators. Such events are sometimes dubbed “Dunkelflaute” events

The following errors in Pirrung et al.1 are corrected here.

No abstract is available for this article.

In Candade et al,1 the authors would like to correct the affiliations of Maximilian Ranneberg2 and Roland Schmehl1.

In this study, an anomaly detection and prediction method for high‐tension bolts is proposed by using the measured strain of tower shell. The finite element models (FEMs) for the high‐tension bolts and tower‐top are built and validated with measurement data. An algorithm of anomaly detection and prediction is then developed by applying Mahalanobis‑Taguchi system. The threshold of abnormal condition

The influence of repair technology of wind turbine blades on the levelized costs of energy (LCOE) is analyzed. The contribution of minor and major failure to the operational expenditures (OPEX) of wind turbines is estimated. It is demonstrated that the minor failure, mainly, surface erosion, is the largest contributor to the unplanned repair, 12 times higher than structural failure. The shortening

Leading edge erosion (LEE) affects almost all wind turbines, reducing their annual energy production and lifetime profitability. This study presents results of an investigation into 18 operational wind farms to assess the validity of the current literature consensus surrounding LEE. Much of the historical research focuses on rain erosion, implying that this is the predominant causal factor. However

The wake dynamics behind a compliant floating offshore wind turbine (FOWT) with two alternative supporting platforms of spar buoy and barge platform are studied numerically. The computational model is based on the large eddy simulation and the use of the actuator disk model of the FOWT rotor in which the circular actuator disk is discretized with an unstructured two‐dimensional triangular mesh in a

Wind farm blockage effects are currently neglected in the prediction of wind farm energy yield, typically leading to an overestimation of the production. This work presents a novel method to assess wind farm production, while accounting for blockage effects. We apply a vortex model, based on a cylindrical wake, to assess induction effects. We present variations of the model to account for finite wake

Previous research has revealed the need for a validation study that considers several wake quantities and code types so that decisions on the trade‐off between accuracy and computational cost can be well informed and appropriate to the intended application. In addition to guiding code choice and setup, rigorous model validation exercises are needed to identify weaknesses and strengths of specific models

This paper considers the time‐varying loads experienced by wind turbine main bearings. Radial load trajectories based on simulated data indicate that ‘looped’ structures, in the form of repeating changes in radial load magnitudes and directions that form elliptical patterns, are present, which have not been described before in the literature. In order to allow these identified structures to be described

Accurate predictions of the wind field are key for better wind power forecasts. Wind speed forecasts from numerical weather models present differences with observations, especially in places with complex topography, such as the north of Chile. The present study has two goals: (a) to find the WRF model boundary layer (PBL) scheme that best reproduces the observations at the Totoral Wind Farm, located

The structural integrity of offshore wind turbine (OWT) support structures is affected by one of the most severe damage mechanisms known as pitting corrosion‐fatigue. In this study, the structural reliability of such structures subjected to pitting corrosion‐fatigue is assessed using a damage tolerance modelling approach. A probabilistic model that ascertains the reliability of the structure is presented

No abstract is available for this article.

Offshore wind turbines have the potential to capture the high‐quality wind resource. However, the significant wind and wave excitations may result in excessive vibrations and decreased reliability. To reduce vibrations, passive structural control devices, such as the tuned mass damper (TMD), have been used. To further enhance the vibration suppression capability, inerter‐based absorbers (IBAs) have

This paper investigates the dynamic modeling and robust control of an underactuated floating wind turbine for vibration suppression. The offshore wind turbine is equipped with a tuned mass damper on the floating platform. The Lagrange's equation is employed to establish the limited degree‐of‐freedom dynamic model. A novel disturbance observer‐based hierarchical sliding mode control system is developed

The distribution of the angles of attack over the span of a rotor blade, together with blade element theory, provides a useful framework to understand forces, performance and other fluid dynamic phenomena of axial‐flow rotors. However, the angle of attack is not straightforward to define for a three‐dimensional rotor, where the flow is perturbed by the blade circulation, shed vorticity and wake development

Efficiency and reliability enhancement of distributed wind energy systems have been the subject of extensive research effort for the purpose of energy cost reduction and power availability. This work investigates the integration of a hydromechanical power split transmission into the drivetrain of a stall‐regulated wind turbine with a fixed‐speed generator to enhance the overall system efficiency without

We propose to mitigate the barge pitch and roll motions of floating hydrostatic wind turbine (HWT) by combining the advantages of the bidirectional tuned liquid column damper (BTLCD) and the tuned mass damper (TMD). This is achieved by enabling the container of the BTLCD to move freely, connecting it to the main structure through springs and dampers, creating what we call a bidirectional tuned liquid

The fast‐growing offshore wind energy sector brings opportunities to provide a sustainable energy resource but also challenges in offshore wind turbine (OWT) operation and maintenance management. Existing operational simulation models assume deterministic input reliability and failure cost data, whereas OWT reliability and failure costs vary depending on several factors, and it is often not possible

Wind energy is running well ahead of its peers to deal with the demand–supply and environmental crisis due to fossil fuels. However, continuous exploitation of land led wind farms built in close proximity of dwellings of human beings, restricted zones, causing adverse effect on health and the environment. In this work, using a widely used model for wake and acoustic model (ISO‐9613‐2), the optimal

This paper presents a preventive maintenance policy for wind turbines considering three effects of wind speed: accelerating hazard rate, restricting maintenance implementation, and affecting downtime cost. The effect on the hazard rate is described by a proportional hazards model. The restriction on maintenance actions results in the elongation of maintenance duration. The downtime cost is evaluated

No abstract is available for this article.

This paper presents a new algorithm based on the combination of fuzzy logic control with M5 decision tree algorithm for doubly fed induction generator active and reactive power control. The M5 model tree is a machine learning algorithm that uses the extracted dataset from fuzzy logic for the aim of control performance enhancement. Because the fuzzy logic provides high design and implementation complexity

An analysis of the effect of low‐level wind maxima (LLWM) below hub height on sound propagating from wind turbines has been performed at a site in northern Sweden. The stably stratified boundary layer, which is typical for cold climates, commonly features LLWM. The simplified concept for the effects of refraction, based on the logarithmic wind profile or other approaches where the wind speed is continuously

In this paper, a STATCOM (static synchronous compensator) is used to encounter the potential SSR (subsynchronous resonance) observed by IG (Induction Generator) based series compensated wind farms. The basic controller used for STATCOM control is identical to that of the literature. An idea of a unique meta‐heuristic swarm‐based optimization technique called BFOA (bacterial foraging optimization algorithm)

A computational model of rain erosion of wind turbine blades is presented. The model is based on the transient fluid–solid coupled finite element (FE) analysis of rain droplet/coating interaction and fatigue degradation analysis. The fatigue analysis of the surface degradation is based on multiaxial fatigue model and critical plane theory. The random rain fields are constructed computationally, and

No abstract is available for this article.

As the size of offshore wind turbines increases, a realistic representation of the spatiotemporal distribution of the incident wind field becomes crucial for modeling the dynamic response of the turbine. The International Electrotechnical Commission (IEC) standard for wind turbine design recommends two turbulence models for simulations of the incident wind field, the Mann spectral tensor model, and

Wind farm control using dynamic concepts is a research topic that is receiving an increasing amount of interest. The main concept of this approach is that dynamic variations of the wind turbine control settings lead to higher wake turbulence, and subsequently faster wake recovery due to increased mixing. As a result, downstream turbines experience higher wind speeds, thus increasing their energy capture

This article deals with nonlinear model‐based control design for wind turbines. By systematically integrating several mechanical degrees of freedom in the control design model, the load mitigation potential from the proposed multivariable control framework is demonstrated. The application of the linear matrix inequality (LMI)‐based control design is discussed in detail. Apart from the commonly considered