scholarly journals Virtual Inertia Coordinated Allocation Method Considering Inertia Demand and Wind Turbine Inertia Response Capability

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5002
Author(s):  
Bo Xu ◽  
Linwei Zhang ◽  
Yin Yao ◽  
Xiangdong Yu ◽  
Yixin Yang ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
System Level ◽  
Evaluation Index ◽  
Synchronous Generators ◽  
Allocation Method ◽  
Virtual Inertia ◽  
Inertia Response ◽  
Response Capability

Wind turbines can have inertia characteristics similar to synchronous generators through virtual inertia control, which helps to provide the inertia support for the system. However, there is the problem of how to coordinate the allocation of virtual inertia among wind turbines. In response to this problem, this paper first analyzes the inertia response capabilities of wind turbines and puts forward an evaluation index that quantifies the inertia response capability of wind turbines. The inertia response capability of a wind farm is evaluated at the entire system level. Based on the evaluation index, the virtual inertia coordinated allocation method considers the system inertia demand and the inertia response capabilities of the wind turbines. It is proposed to release the inertia response capability of each wind turbine while avoiding an excessive release of kinetic energy and bring a second impact by wind turbines’ exiting operation. Finally, the effectiveness of the proposed method is verified by a simulation case study.

scholarly journals Impact of Economic Indicators on the Integrated Design of Wind Turbine Systems

2018 ◽  
Vol 8 (9) ◽  
pp. 1668 ◽  
Author(s):  
Jianghai Wu ◽  
Tongguang Wang ◽  
Long Wang ◽  
Ning Zhao
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Energy Production ◽  
Large Scale ◽  
Wind Farm ◽  
Net Present Value ◽  
Integrated Design ◽  
Aerodynamic Performance ◽  
System Level ◽  
Blade Length

This article presents a framework to integrate and optimize the design of large-scale wind turbines. Annual energy production, load analysis, the structural design of components and the wind farm operation model are coupled to perform a system-level nonlinear optimization. As well as the commonly used design objective levelized cost of energy (LCoE), key metrics of engineering economics such as net present value (NPV), internal rate of return (IRR) and the discounted payback time (DPT) are calculated and used as design objectives, respectively. The results show that IRR and DPT have the same effect as LCoE since they all lead to minimization of the ratio of the capital expenditure to the energy production. Meanwhile, the optimization for NPV tends to maximize the margin between incomes and costs. These two types of economic metrics provide the minimal blade length and maximal blade length of an optimal blade for a target wind turbine at a given wind farm. The turbine properties with respect to the blade length and tower height are also examined. The blade obtained with economic optimization objectives has a much larger relative thickness and smaller chord distributions than that obtained for high aerodynamic performance design. Furthermore, the use of cost control objectives in optimization is crucial in improving the economic efficiency of wind turbines and sacrificing some aerodynamic performance can bring significant reductions in design loads and turbine costs.

scholarly journals DFIG wind turbine under unbalanced power system conditions using adaptive fuzzy virtual inertia controller

Energetika ◽  
2019 ◽  
Vol 65 (1) ◽  
Author(s):  
Mohamed Zellagui ◽  
Heba Ahmed Hassan ◽  
Mohamed Nassim Kraimia
Keyword(s):  
Power System ◽  
Wind Turbines ◽  
Wind Farm ◽  
Frequency Stability ◽  
Area Network ◽  
Negative Effects ◽  
Adaptive Fuzzy ◽  
Point Tracking ◽  
Virtual Inertia ◽  
Inertia Response

The Doubly-Fed Induction Generator (DFIG) based Wind Turbines Generator (WTG) with traditional Maximum Power Point Tracking (MPPT) control provides no inertia response under system frequency events. Recently, the DFIG wind turbines have been equipped with the Virtual Inertia Controller (VIC) to enhance the frequency stability of the power system. However, the conventional VICs with fixed gain have negative effects on the inter-area oscillations of regional networks. To cope with this drawback, this paper proposes a novel adaptive VIC to improve both the inter-area oscillations and frequency stability. In the proposed scheme, the gain of the VIC is dynamically adjusted using fuzzy logic. The effectiveness and control performance of the adaptive fuzzy VIC is evaluated under different frequency events such as loss of generation and three-phase fault with load shedding. The simulation studies are performed on a generic two-area network integrated with a DFIG wind farm, and the comparative results are presented for these three cases: DFIG without VIC, DFIG with fixed gain VIC, and DFIG with adaptive fuzzy VIC. The results confirm the ability of the proposed adaptive fuzzy VIC in improving both the interarea oscillations and frequency stability of the system.

Fatigue Life Analysis of Offshore Wind Turbine Support Structures in an Offshore Wind Farm

2018 ◽  
Author(s):  
Bryan Nelson ◽  
Yann Quéméner
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
The Body ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Analysis Tool ◽  
Support Structures ◽  
Offshore Wind Farm ◽  
Actuator Disk

This study evaluated, by time-domain simulations, the fatigue lives of several jacket support structures for 4 MW wind turbines distributed throughout an offshore wind farm off Taiwan’s west coast. An in-house RANS-based wind farm analysis tool, WiFa3D, has been developed to determine the effects of the wind turbine wake behaviour on the flow fields through wind farm clusters. To reduce computational cost, WiFa3D employs actuator disk models to simulate the body forces imposed on the flow field by the target wind turbines, where the actuator disk is defined by the swept region of the rotor in space, and a body force distribution representing the aerodynamic characteristics of the rotor is assigned within this virtual disk. Simulations were performed for a range of environmental conditions, which were then combined with preliminary site survey metocean data to produce a long-term statistical environment. The short-term environmental loads on the wind turbine rotors were calculated by an unsteady blade element momentum (BEM) model of the target 4 MW wind turbines. The fatigue assessment of the jacket support structure was then conducted by applying the Rainflow Counting scheme on the hot spot stresses variations, as read-out from Finite Element results, and by employing appropriate SN curves. The fatigue lives of several wind turbine support structures taken at various locations in the wind farm showed significant variations with the preliminary design condition that assumed a single wind turbine without wake disturbance from other units.

scholarly journals A Review of Recent Advancements in Offshore Wind Turbine Technology

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 579
Author(s):  
Taimoor Asim ◽  
Sheikh Zahidul Islam ◽  
Arman Hemmati ◽  
Muhammad Saif Ullah Khalid
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Structural Integrity ◽  
Turbine Blades ◽  
Offshore Wind ◽  
System Level ◽  
Offshore Wind Turbine ◽  
Component Level ◽  
Foundation Design ◽  
Offshore Wind Turbines

Offshore wind turbines are becoming increasingly popular due to their higher wind energy harnessing capabilities and lower visual pollution. Researchers around the globe have been reporting significant scientific advancements in offshore wind turbines technology, addressing key issues, such as aerodynamic characteristics of turbine blades, dynamic response of the turbine, structural integrity of the turbine foundation, design of the mooring cables, ground scouring and cost modelling for commercial viability. These investigations range from component-level design and analysis to system-level response and optimization using a multitude of analytical, empirical and numerical techniques. With such wide-ranging studies available in the public domain, there is a need to carry out an extensive yet critical literature review on the recent advancements in offshore wind turbine technology. Offshore wind turbine blades’ aerodynamics and the structural integrity of offshore wind turbines are of particular importance, which can lead towards system’s optimal design and operation, leading to reduced maintenance costs. Thus, in this study, our focus is to highlight key knowledge gaps in the scientific investigations on offshore wind turbines’ aerodynamic and structural response. It is envisaged that this study will pave the way for future concentrated efforts in better understanding the complex behavior of these machines.

scholarly journals Correlations of power output fluctuations in an offshore wind farm using high-resolution SCADA data

2021 ◽  
Vol 6 (4) ◽  
pp. 997-1014
Author(s):  
Janna Kristina Seifert ◽  
Martin Kraft ◽  
Martin Kühn ◽  
Laura J. Lukassen
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Power Output ◽  
Wind Farm ◽  
Offshore Wind ◽  
Offshore Wind Farm ◽  
Flow Conditions ◽  
Output Fluctuations ◽  
Power Difference ◽  
Time Correlations

Abstract. Space–time correlations of power output fluctuations of wind turbine pairs provide information on the flow conditions within a wind farm and the interactions of wind turbines. Such information can play an essential role in controlling wind turbines and short-term load or power forecasting. However, the challenges of analysing correlations of power output fluctuations in a wind farm are the highly varying flow conditions. Here, we present an approach to investigate space–time correlations of power output fluctuations of streamwise-aligned wind turbine pairs based on high-resolution supervisory control and data acquisition (SCADA) data. The proposed approach overcomes the challenge of spatially variable and temporally variable flow conditions within the wind farm. We analyse the influences of the different statistics of the power output of wind turbines on the correlations of power output fluctuations based on 8 months of measurements from an offshore wind farm with 80 wind turbines. First, we assess the effect of the wind direction on the correlations of power output fluctuations of wind turbine pairs. We show that the correlations are highest for the streamwise-aligned wind turbine pairs and decrease when the mean wind direction changes its angle to be more perpendicular to the pair. Further, we show that the correlations for streamwise-aligned wind turbine pairs depend on the location of the wind turbines within the wind farm and on their inflow conditions (free stream or wake). Our primary result is that the standard deviations of the power output fluctuations and the normalised power difference of the wind turbines in a pair can characterise the correlations of power output fluctuations of streamwise-aligned wind turbine pairs. Further, we show that clustering can be used to identify different correlation curves. For this, we employ the data-driven k-means clustering algorithm to cluster the standard deviations of the power output fluctuations of the wind turbines and the normalised power difference of the wind turbines in a pair. Thereby, wind turbine pairs with similar power output fluctuation correlations are clustered independently from their location. With this, we account for the highly variable flow conditions inside a wind farm, which unpredictably influence the correlations.

Health Assessment Methods for Wind Turbines Based on Power Prediction and Mahalanobis Distance

2018 ◽  
Vol 33 (02) ◽  
pp. 1951001 ◽  
Author(s):  
Jun Zhan ◽  
Ronglin Wang ◽  
Lingzhi Yi ◽  
Yaguo Wang ◽  
Zhengjuan Xie
Keyword(s):  
Health Status ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Mahalanobis Distance ◽  
Wind Farm ◽  
Health Status Assessment ◽  
Power Prediction ◽  
Residual Set ◽  
Scada System ◽  
Status Assessment

The output power of wind turbine has great relation with its health state, and the health status assessment for wind turbines influences operational maintenance and economic benefit of wind farm. Aiming at the current problem that the health status for the whole machine in wind farm is hard to get accurately, in this paper, we propose a health status assessment method in order to assess and predict the health status of the whole wind turbine, which is based on the power prediction and Mahalanobis distance (MD). Firstly, on the basis of Bates theory, the scientific analysis for historical data from SCADA system in wind farm explains the relation between wind power and running states of wind turbines. Secondly, the active power prediction model is utilized to obtain the power forecasting value under the health status of wind turbines. And the difference between the forecasting value and actual value constructs the standard residual set which is seen as the benchmark of health status assessment for wind turbines. In the process of assessment, the test set residual is gained by network model. The MD is calculated by the test residual set and normal residual set and then normalized as the health status assessment value of wind turbines. This method innovatively constructs evaluation index which can reflect the electricity generating performance of wind turbines rapidly and precisely. So it effectively avoids the defect that the existing methods are generally and easily influenced by subjective consciousness. Finally, SCADA system data in one wind farm of Fujian province has been used to verify this method. The results indicate that this new method can make effective assessment for the health status variation trend of wind turbines and provide new means for fault warning of wind turbines.

scholarly journals Impedance Aggregation Method of Multiple Wind Turbines and Accuracy Analysis

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2035 ◽  
Author(s):  
Liang Chen ◽  
Heng Nian ◽  
Yunyang Xu
Keyword(s):  
Stability Analysis ◽  
Reference Frame ◽  
Wind Turbines ◽  
Power Distribution ◽  
Wind Farm ◽  
System Level ◽  
Small Signal ◽  
Impedance Model ◽  
The Stability ◽  
The Impact

The sequence domain impedance modeling of wind turbines (WTs) has been widely used in the stability analysis between WTs and weak grids with high line impedance. An aggregated impedance model of the wind farm is required in the system-level analysis. However, directly aggregating WT small-signal impedance models will lead to an inaccurate aggregated impedance model due to the mismatch of reference frame definitions among different WT subsystems, which may lead to inaccuracy in the stability analysis. In this paper, we analyze the impacts of the reference frame mismatch between a local small-signal impedance model and a global one on the accuracy of aggregated impedance and the accuracy of impedance-based stability analysis. The results revealed that the impact is related to the power distribution of the studied network. It was found that that the influence of mismatch on stability analysis became subtle when subsystems were balanced loaded. Considering that balanced loading is a common configuration of the practical application, direct impedance aggregation by local small-signal models can be applied due to its acceptable accuracy.

scholarly journals Floating Performance of a Composite Bucket Foundation with an Offshore Wind Tower during Transportation

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 882 ◽  
Author(s):  
Hongyan Ding ◽  
Zuntao Feng ◽  
Puyang Zhang ◽  
Conghuan Le ◽  
Yaohua Guo
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Wind Farms ◽  
Interaction Force ◽  
Offshore Wind ◽  
Construction Technique ◽  
Bucket Foundation ◽  
Offshore Wind Turbines ◽  
One Step

The composite bucket foundation (CBF) for offshore wind turbines is the basis for a one-step integrated transportation and installation technique, which can be adapted to the construction and development needs of offshore wind farms due to its special structural form. To transport and install bucket foundations together with the upper portion of offshore wind turbines, a non-self-propelled integrated transportation and installation vessel was designed. In this paper, as the first stage of applying the proposed one-step integrated construction technique, the floating behavior during the transportation of CBF with a wind turbine tower for the Xiangshui wind farm in the Jiangsu province was monitored. The influences of speed, wave height, and wind on the floating behavior of the structure were studied. The results show that the roll and pitch angles remain close to level during the process of lifting and towing the wind turbine structure. In addition, the safety of the aircushion structure of the CBF was verified by analyzing the measurement results for the interaction force and the depth of the liquid within the bucket. The results of the three-DOF (degree of freedom) acceleration monitoring on the top of the test tower indicate that the wind turbine could meet the specified acceleration value limits during towing.

Floating Offshore Wind Turbines: Responses in a Seastate Pareto Optimal Designs and Economic Assessment

2008 ◽  
Author(s):  
Paul Sclavounos ◽  
Christopher Tracy ◽  
Sungho Lee
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Wind Farms ◽  
Economic Assessment ◽  
Offshore Wind ◽  
Pareto Optimal ◽  
Mooring System ◽  
Floating Structure ◽  
Water Depths

Wind is the fastest growing renewable energy source, increasing at an annual rate of 25% with a worldwide installed capacity of 74 GW in 2007. The vast majority of wind power is generated from onshore wind farms. Their growth is however limited by the lack of inexpensive land near major population centers and the visual pollution caused by large wind turbines. Wind energy generated from offshore wind farms is the next frontier. Large sea areas with stronger and steadier winds are available for wind farm development and 5MW wind turbine towers located 20 miles from the coastline are invisible. Current offshore wind turbines are supported by monopoles driven into the seafloor at coastal sites a few miles from shore and in water depths of 10–15m. The primary impediment to their growth is visual pollution and the prohibitive cost of seafloor mounted monopoles in larger water depths. This paper presents a fully coupled dynamic analysis of floating wind turbines that enables a parametric design study of floating wind turbine concepts and mooring systems. Pareto optimal designs are presented that possess a favorable combination of nacelle acceleration, mooring system tension and displacement of the floating structure supporting a five megawatt wind turbine. All concepts are selected so that they float stably while in tow to the offshore wind farm site and prior to their connection to the mooring system. A fully coupled dynamic analysis is carried out of the wind turbine, floater and mooring system in wind and a sea state based on standard computer programs used by the offshore and wind industries. The results of the parametric study are designs that show Pareto fronts for mean square acceleration of the turbine versus key cost drivers for the offshore structure that include the weight of the floating structure and the static plus dynamic mooring line tension. Pareto optimal structures are generally either a narrow deep drafted spar, or a shallow drafted barge ballasted with concrete. The mooring systems include both tension leg and catenary mooring systems. In some of the designs, the RMS acceleration of the wind turbine nacelle can be as low as 0.03 g in a sea state with a significant wave height of ten meters and water depths of up to 200 meters. These structures meet design requirements while possessing a favorable combination of nacelle accleration, total mooring system tension and weight of the floating structure. Their economic assessment is also discussed drawing upon a recent financial analysis of a proposed offshore wind farm.

Progressive Drift of Moored Floating Wind Turbines in a Wind Farm: Improved Mooring Capacity Model

2011 ◽  
Author(s):  
Hideyuki Suzuki ◽  
Yu Kitahara ◽  
Yukinari Fukumoto
Keyword(s):  
Wind Turbine ◽  
Safety Factor ◽  
Wind Turbines ◽  
Wind Farm ◽  
Wind Farms ◽  
Floating Platform ◽  
Main Research ◽  
Electric Power Supply ◽  
Analysis And Design ◽  
Wide Range

A wide range of platform concepts have been investigated for a floating wind turbine. So far analysis and design of motion characteristics of the platform is main research concern. One key research area less focused is floating platform related risk. If the wind energy would be one of the major sources of electric power supply, wind farms which are comprised of large number of floating wind turbines must be deployed in the ocean. Wind turbines are relatively closely arranged in a wind farm. In such an arrangement, a wind turbine accidentally started drifting will have some possibility to collide with floater and moorings of neighboring moored floating wind turbines, and might initiate another drift which might cause progressive drifting of wind turbines. In the previous report, a scenario of progressive drifting of wind turbines was investigated and associated risk was formulated. Quantitative risk of several arrangements of wind farm was estimated. Effects of arrangement of wind turbines in a wind farm and safety factor used in the design of moorings is discussed. Probability of initial drift was evaluated analyzing past records of accidents and design of mooring. In this research, strength of mooring system was modeled more precisely and probabilistic model was developed considering aged deterioration. Risk of progressive drifting was evaluated and safety factor required to realize a acceptable risk of a wind farm was discussed.

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