Assessing the Importance of Geometric Nonlinear Effects in the Prediction of Wind Turbine Blade Loads

2015 ◽  
Vol 10 (4) ◽  
Author(s):  
D. I. Manolas ◽  
V. A. Riziotis ◽  
S. G. Voutsinas
Keyword(s):  
Wind Turbine ◽  
Nonlinear Effects ◽  
Normal Operation ◽  
Order Model ◽  
Multibody Model ◽  
Operation Conditions ◽  
Geometric Nonlinear ◽  
Structural Nonlinearities ◽  
Clear Shift ◽  
Blade Loads

As the size of commercial wind turbines increases, new blade designs become more flexible in order to comply with the requirement for reduced weights. In normal operation conditions, flexible blades undergo large bending deflections, which exceed 10% of their radius, while significant torsion angles toward the tip of the blade are obtained, which potentially affect performance and stability. In the present paper, the effects on the loads of a wind turbine from structural nonlinearities induced by large deflections of the blades are assessed, based on simulations carried out for the NREL 5 MW wind turbine. Two nonlinear beam models, a second order (2nd order) model and a multibody model that both account for geometric nonlinear structural effects, are compared to a first order beam (1st order) model. Deflections and loads produced by finite element method based aero-elastic simulations using these three models show that the bending–torsion coupling is the main nonlinear effect that drives differences on loads. The main effect on fatigue loads is the over 100% increase of the torsion moment, having obvious implications on the design of the pitch bearings. In addition, nonlinearity leads to a clear shift in the frequencies of the second edgewise modes.

scholarly journals Vestas V90-3MW Wind Turbine Gearbox Health Assessment Using a Vibration-Based Condition Monitoring System

2016 ◽  
Vol 2016 ◽  
pp. 1-18 ◽  
Author(s):  
A. Romero ◽  
Y. Lage ◽  
S. Soua ◽  
B. Wang ◽  
T.-H. Gan
Keyword(s):  
Fault Diagnosis ◽  
Wind Turbine ◽  
Condition Monitoring ◽  
Learning Algorithm ◽  
Health Assessment ◽  
Field Trials ◽  
Health Condition ◽  
Normal Operation ◽  
Wind Turbine Gearbox ◽  
Operation Conditions

Reliable monitoring for the early fault diagnosis of gearbox faults is of great concern for the wind industry. This paper presents a novel approach for health condition monitoring (CM) and fault diagnosis in wind turbine gearboxes using vibration analysis. This methodology is based on a machine learning algorithm that generates a baseline for the identification of deviations from the normal operation conditions of the turbine and the intrinsic characteristic-scale decomposition (ICD) method for fault type recognition. Outliers picked up during the baseline stage are decomposed by the ICD method to obtain the product components which reveal the fault information. The new methodology proposed for gear and bearing defect identification was validated by laboratory and field trials, comparing well with the methods reviewed in the literature.

Vibrations of a Three-Bladed Wind Turbine Rotor Due to Classical Flutter

2002 ◽  
Author(s):  
M. H. Hansen
Keyword(s):  
Wind Turbine ◽  
Critical Frequency ◽  
Turbine Blades ◽  
Turbine Rotor ◽  
Normal Operation ◽  
Aerodynamic Damping ◽  
Operation Conditions ◽  
Torsional Frequency ◽  
Classical Flutter ◽  
Wind Turbine Rotor

The aeroelastic stability of a three-bladed wind turbine is considered with respect to classical flutter. Previous studies have shown that the risk of stall-induced vibrations of turbine blades is related to the dynamics of the complete turbine, for example does the aerodynamic damping of a rotor whirling mode depend highly on the tower stiffness. The results of this paper indicate that the turbine dynamics also affect the risk of flutter. The study is based on an eigenvalue analysis of a linear aeroelastic turbine model. In an example of a MW sized turbine, the critical frequency of the first torsional blade mode is determined for which flutter can occur under normal operation conditions. It is shown that this critical torsional frequency is higher when the blades are interacting through the hub with the remaining turbine, than when all blades are rigidly clamped at the root. Thus, the dynamics of the turbine has increased the risk of flutter.

Dynamic Analysis of the Wind Turbine Tower

2013 ◽  
Vol 790 ◽  
pp. 651-654
Author(s):  
Chi Chen ◽  
Hong Bo Shen ◽  
Min Wang
Keyword(s):  
Dynamic Analysis ◽  
Wind Turbine ◽  
Natural Frequencies ◽  
Safety Evaluation ◽  
Model Analysis ◽  
Rotational Frequency ◽  
Normal Operation ◽  
Transient Dynamic Analysis ◽  
Operation Conditions ◽  
Wind Turbine Tower

In this thesis, the conical tower of domestic popular 1.5MW wind turbine is analyzed in dynamic by using the software ANSYS. The natural frequencies can be extracted from the model analysis results, comparing them with the impeller rotational frequency and determining whether the tower will resonate when the wind turbine under normal operation conditions. Based on the model analysis, the transient dynamic analysis is carried out by inputting the history records of seismic wave acceleration, Both these two analysis can provide the basis for the safety evaluation of the tower.

scholarly journals Adaptive Machine Learning Approach for Fault Prognostics based on Normal Conditions - Application to Shaft Bearings of Wind Turbine

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Koceila Abid ◽  
Moamar Sayed-Mouchaweh ◽  
Cornez Laurence
Keyword(s):  
Wind Turbine ◽  
High Speed ◽  
Remaining Useful Life ◽  
Normal Operation ◽  
Maintenance Cost ◽  
Support Vector ◽  
Industrial Systems ◽  
Operation Conditions ◽  
Degradation Data ◽  
Fault Prognostics

Prognostics can enhance the reliability and availability of industrial systems while reducing unscheduled faults and maintenance cost. In real industrial systems, data collected from the normal operation conditions of system is available, but there is a lack of historical degradation data is often unavailable. Hence, this paper proposes a general data-driven prognostic approach dealing with the lack of degradation data in the offline phase. First, features are computed on the collected raw signal, then One Class Support Vector Machine (OCSVM) is used to detect the degradation, this anomaly detection method is trained using only normal operation data. Then, features are ranked according to the selection criteria. The feature having the highest score is chosen as Health Indicator (HI). Finally an adaptive degradation model is applied for the prediction of the degradation evolution over time and Remaining Useful Life (RUL) estimation. The proposed approach is validated using run-to-failure vibration data collected from a high speed shaft bearings of a commercial wind turbine.

scholarly journals Modelling, Design and Control of a Standalone Hybrid PV-Wind Micro-Grid System

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4849
Author(s):  
Ayman Al-Quraan ◽  
Muhannad Al-Qaisi
Keyword(s):  
Wind Turbine ◽  
State Of Charge ◽  
Maximum Power ◽  
Normal Operation ◽  
Grid System ◽  
Pv System ◽  
Remote Areas ◽  
Operation Conditions ◽  
Pv Panel ◽  
Micro Grid

The problem of electrical power delivery is a common problem, especially in remote areas where electrical networks are difficult to reach. One of the ways that is used to overcome this problem is the use of networks separated from the electrical system through which it is possible to supply electrical energy to remote areas. These networks are called standalone microgrid systems. In this paper, a standalone micro-grid system consisting of a Photovoltaic (PV) and Wind Energy Conversion System (WECS) based Permanent Magnet Synchronous Generator (PMSG) is being designed and controlled. Fuzzy logic-based Maximum Power Point Tracking (MPPT) is being applied to a boost converter to control and extract the maximum power available for the PV system. The control system is designed to deliver the required energy to a specific load, in all scenarios. The excess energy generated by the PV panel is used to charge the batteries when the energy generated by the PV panel exceeds the energy required by the load. When the electricity generated by the PV panels is insufficient to meet the load’s demands, the extra power is extracted from the charged batteries. In addition, the controller protects the battery banks in all conditions, including normal, overcharging, and overdischarging conditions. The controller should handle each case correctly. Under normal operation conditions (20% < State of Charge (SOC) < 80%), the controller functions as expected, regardless of the battery’s state of charge. When the SOC reaches 80%, a specific command is delivered, which shuts off the PV panel and the wind turbine. The PV panel and wind turbine cannot be connected until the SOC falls below a safe margin value of 75% in this controller. When the SOC goes below 20%, other commands are sent out to turn off the inverter and disconnect the loads. The electricity to the inverter is turned off until the batteries are charged again to a suitable value.

Assessment of the strain gauge technique for measurement of wind turbine blade loads

Wind Energy ◽  
2000 ◽  
Vol 3 (1) ◽  
pp. 35-65 ◽  
Author(s):  
K. Papadopoulos ◽  
E. Morfiadakis ◽  
T. P. Philippidis ◽  
D. J. Lekou
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Strain Gauge ◽  
Wind Turbine Blade ◽  
Blade Loads

scholarly journals Criticality safety analysis of spent fuel pool for a PWR using UO2, MOX, (Th-U)O2 and (TRU-Th)O2 fuels

2019 ◽  
Vol 7 (3A) ◽  
Author(s):  
Claubia Pereira ◽  
Jéssica P. Achilles ◽  
Fabiano Cardoso ◽  
Victor F. Castro ◽  
Maria Auxiliadora F. Veloso
Keyword(s):  
Normal Operation ◽  
Pressurized Water Reactor ◽  
Spent Fuel ◽  
Pressurized Water ◽  
Operation Conditions ◽  
Transport Code ◽  
Uranium Fuel ◽  
Fuel Assemblies ◽  
Spent Fuel Pool ◽  
Criticality Safety

A spent fuel pool of a typical Pressurized Water Reactor (PWR) was evaluated for criticality studies when it uses reprocessed fuels. PWR nuclear fuel assemblies with four types of fuels were considered: standard PWR fuel, MOX fuel, thorium-uranium fuel and reprocessed transuranic fuel spiked with thorium. The MOX and UO2 benchmark model was evaluated using SCALE 6.0 code with KENO-V transport code and then, adopted as a reference for other fuels compositions. The four fuel assemblies were submitted to irradiation at normal operation conditions. The burnup calculations were obtained using the TRITON sequence in the SCALE 6.0 code package. The fuel assemblies modeled use a benchmark 17x17 PWR fuel assembly dimensions. After irradiation, the fuels were inserted in the pool. The criticality safety limits were performed using the KENO-V transport code in the CSAS5 sequence. It was shown that mixing a quarter of reprocessed fuel withUO2 fuel in the pool, it would not need to be resized 

scholarly journals Full field assessment of wind turbine near wake deviation in relation to yaw misalignment

2016 ◽  
Author(s):  
Juan-José Trujillo ◽  
Janna K. Seifert ◽  
Ines Würth ◽  
David Schlipf ◽  
Martin Kühn
Keyword(s):  
Wind Turbine ◽  
Tip Vortex ◽  
Offshore Wind ◽  
Normal Operation ◽  
Offshore Wind Turbine ◽  
Near Wake ◽  
Thrust Coefficient ◽  
Full Field ◽  
Wake Field ◽  
Partial Load

Abstract. Presently there is a lack of data revealing the behaviour of the path followed by the near wake of full scale wind turbines and its dependence on yaw misalignment. Here we present an experimental analysis of the horizontal wake deviation of a 5 MW offshore wind turbine between 0.6 and 1.4 diameters downstream. The wake field has been scanned with a short range lidar and the wake path has been reconstructed by means of two-dimensional Gaussian tracking. We analysed the measurements for rotor yaw misalignments arising in normal operation and during partial load, representing high thrust coefficient conditions. We classified distinctive wake paths with reference to yaw misalignment, based on the nacelle wind vane, in steps of 3° in a range of ±10.5°. All paths observed in the nacelle frame of reference showed a consistent convergence towards 0.9 rotor diameters downstream suggesting a kind of wake deviation delay. This contrasts with published results from wind tunnels which in general report a convergence towards the rotor. The discrepancy is evidenced in particular in a comparison which we performed against published paths obtained by means of tip vortex tracking.

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