scholarly journals Frequency support scheme based on parametrized power curve for de-loaded wind turbine under various wind speed

2021 ◽  
pp. 0309524X2110351
Author(s):  
Cheng Zhong ◽  
Yueming Lv ◽  
Huayi Li ◽  
JiKai Chen ◽  
Yang Li
Keyword(s):  
Wind Speed ◽  
Power Systems ◽  
Wind Turbines ◽  
Frequency Regulation ◽  
Measurement Information ◽  
Stable Operation ◽  
Rotor Speed ◽  
Wind Speeds ◽  
Regulation Scheme ◽  
Frequency Controller

With increased wind power penetration in modern power systems, wind plants are required to provide frequency support similar to conventional plants. However, for the existing frequency regulation scheme of wind turbines, the control gains in the auxiliary frequency controller are difficult to set because of the compromise of the frequency regulation performance and the stable operation of wind turbines, especially when the wind speed remains variable. This paper proposes a novel frequency regulation scheme (FRS) for de-loaded wind turbines. Instead of an auxiliary frequency controller, frequency support is provided by modifying the parametrized power versus rotor speed ( Pw-ω r) curve, including the inertia power versus rotor speed curve and the droop power versus rotor speed curve. The advantage of the proposed scheme is that it does not contain any control gains and generally adapts to different wind speeds. Further, the proposed scheme can work for the whole section of wind speed without wind speed measurement information. The compared simulation results demonstrate the scheme improves the system frequency response while ensuring the stable operation of doubly-fed induction generators (DFIGs)-based variable-speed wind turbines (VSWTs) under various wind conditions. Furthermore, the scheme prevents rotor speed overdeceleration even when the wind speed decreases during frequency regulation control.

scholarly journals Analysis of the Implementation of the Primary and/or Inertial Frequency Control in Variable Speed Wind Turbines in an Isolated Power System with High Renewable Penetration. Case Study: El Hierro Power System

Electronics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 901 ◽  
Author(s):  
Guillermo Martínez-Lucas ◽  
José Ignacio Sarasúa ◽  
Juan Ignacio Pérez-Díaz ◽  
Sergio Martínez ◽  
Danny Ochoa
Keyword(s):  
Wind Speed ◽  
Power Systems ◽  
Power System ◽  
Wind Turbines ◽  
Wind Farm ◽  
Frequency Control ◽  
Frequency Regulation ◽  
Variable Speed ◽  
El Hierro

With high levels of wind energy penetration, the frequency response of isolated power systems is more likely to be affected in the event of a sudden frequency disturbance or fluctuating wind conditions. In order to minimize excessive frequency deviations, several techniques and control strategies involving Variable Speed Wind Turbines (VSWTs) have been investigated in isolated power systems. In this paper, the main benefits and disadvantages of introducing VSWTs—both their inertial contribution and primary frequency regulation—in an exclusively renewable isolated power system have been analyzed. Special attention has been paid to the influence of the delays of control signals in the wind farm when VSWTs provide primary regulation as well as to the wind power reserve value which is needed. To achieve this objective, a methodology has been proposed and applied to a case study: El Hierro power system. A mathematical dynamic model of the isolated power system, including exclusively renewable technologies, has been described. Representative generation schedules and wind speed signals have been fixed according to the observed system. Finally, in order to obtain conclusions, realistic system events such as fluctuations in wind speed and the outage of the generation unit with the higher assigned power in the power system have been simulated.

scholarly journals Analysis of Doubly Fed Induction Generators Participating in Continuous Frequency Regulation with Different Wind Speeds Considering Regulation Power Constraints

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 635 ◽  
Author(s):  
Tingting Cai ◽  
Sutong Liu ◽  
Gangui Yan ◽  
Hongbo Liu
Keyword(s):  
Power Systems ◽  
Wind Farm ◽  
Frequency Regulation ◽  
Adjustment Coefficient ◽  
Rotor Speed ◽  
Wind Speeds ◽  
Power Constraints ◽  
Bidirectional Regulation ◽  
Continuous Frequency ◽  
Doubly Fed

Wind turbines (WTs) participate in frequency regulation, which is one of the means to solve the problem of inadequate regulation capacity in power systems with a high proportion of renewable energy. The doubly fed induction generator (DFIG) can reserve part of power to achieve bidirectional regulation capability through rotor over-speed and increasing pitch angle. In this paper, it is pointed out that the available bidirectional regulation power of the WT is constrained by the maximum regulation power under the rotor speed regulation. The regulation power constraints under the pitch regulation considering the time scale are calculated. The adjustment coefficient of WT participating in frequency regulation is designed. Considering the regulation power constraints, the frequency difference interval in which the WT can provide the regulation power according to the adjustment coefficient is analyzed. The rotor speed and pitch coordinated control strategy of DFIG with different wind speeds is designed. Based on 24-hour measured data from a wind farm, the power constraints and their effects of WTs in the wind farm participating in frequency regulation are verified by simulation. The regulation power of the wind farm, frequency quality, and wind power utilization under the different control strategies are analyzed. The results show that the effects of bidirectional power constraints must be taken into account when evaluating the effectiveness of WTs in continuous frequency regulation.

SHAPING OF AN AUTONOMOUS POWER SYSTEM FOR GUARANTEED POWER SUPPLY WITH THE PREDOMINANCE WIND ENERGY

2018 ◽  
pp. 28-50
Author(s):  
S. G. Ignatiev ◽  
S. V. Kiseleva
Keyword(s):  
Energy Storage ◽  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Energy Demand ◽  
Diesel Generator ◽  
Average Wind Speed ◽  
Wind Speeds ◽  
Average Wind

Optimization of the autonomous wind-diesel plants composition and of their power for guaranteed energy supply, despite the long history of research, the diversity of approaches and methods, is an urgent problem. In this paper, a detailed analysis of the wind energy characteristics is proposed to shape an autonomous power system for a guaranteed power supply with predominance wind energy. The analysis was carried out on the basis of wind speed measurements in the south of the European part of Russia during 8 months at different heights with a discreteness of 10 minutes. As a result, we have obtained a sequence of average daily wind speeds and the sequences constructed by arbitrary variations in the distribution of average daily wind speeds in this interval. These sequences have been used to calculate energy balances in systems (wind turbines + diesel generator + consumer with constant and limited daily energy demand) and (wind turbines + diesel generator + consumer with constant and limited daily energy demand + energy storage). In order to maximize the use of wind energy, the wind turbine integrally for the period in question is assumed to produce the required amount of energy. For the generality of consideration, we have introduced the relative values of the required energy, relative energy produced by the wind turbine and the diesel generator and relative storage capacity by normalizing them to the swept area of the wind wheel. The paper shows the effect of the average wind speed over the period on the energy characteristics of the system (wind turbine + diesel generator + consumer). It was found that the wind turbine energy produced, wind turbine energy used by the consumer, fuel consumption, and fuel economy depend (close to cubic dependence) upon the specified average wind speed. It was found that, for the same system with a limited amount of required energy and high average wind speed over the period, the wind turbines with lower generator power and smaller wind wheel radius use wind energy more efficiently than the wind turbines with higher generator power and larger wind wheel radius at less average wind speed. For the system (wind turbine + diesel generator + energy storage + consumer) with increasing average speed for a given amount of energy required, which in general is covered by the energy production of wind turbines for the period, the maximum size capacity of the storage device decreases. With decreasing the energy storage capacity, the influence of the random nature of the change in wind speed decreases, and at some values of the relative capacity, it can be neglected.

scholarly journals Wind Turbulence Intensity at La Ventosa, Mexico: A Comparative Study with the IEC61400 Standards

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3007 ◽  
Author(s):  
C. Lopez-Villalobos ◽  
O. Rodriguez-Hernandez ◽  
R. Campos-Amezcua ◽  
Guillermo Hernandez-Cruz ◽  
O. Jaramillo ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Turbines ◽  
Turbulence Intensity ◽  
Structural Damage ◽  
Atmospheric Stability ◽  
Design Parameters ◽  
Power Sector ◽  
Wind Speeds ◽  
Technical Solutions ◽  
Large Wind

Wind speed turbulence intensity is a crucial parameter in designing the structure of wind turbines. The IEC61400 considers the Normal Turbulence Model (NTM) as a reference for fatigue load calculations for small and large wind turbines. La Ventosa is a relevant region for the development of the wind power sector in Mexico. However, in the literature, there are no studies on this important parameter in this zone. Therefore, we present an analysis of the turbulence intensity to improve the understanding of local winds and contribute to the development of reliable technical solutions. In this work, we experimentally estimate the turbulence intensity of the region and the wind shear exponent in terms of atmospheric stability to analyze the relation of these design parameters with the recommended standard for large and small wind turbines. The results showed that the atmosphere is strongly convective and stable in most of the eleven months studied. The turbulence intensity analysis showed that for a range of wind speeds between 2 and 24 m/s, some values of the variable measured were greater than those recommended by the standard, which corresponds to 388 hours of turbulence intensity being underestimated. This may lead to fatigue loads and cause structural damage to the technologies installed in the zone if they were not designed to operate in these wind speed conditions.

Analysis of Wind Field Fan Based on Performance Enhancement Method

2014 ◽  
Vol 986-987 ◽  
pp. 235-238
Author(s):  
Xiao Long Tan ◽  
Jia Zhou ◽  
Wen Bin Wang
Keyword(s):  
Wind Speed ◽  
Wind Turbines ◽  
Performance Enhancement ◽  
Aerodynamic Performance ◽  
Wind Load ◽  
Wind Speeds ◽  
Enhancement Method ◽  
Changes Over Time ◽  
Load Simulation ◽  
Single Constant

For the simulation of wind turbine, the wind speed is extremely important parameters and indicators to measure the output power of the unit is the wind load. Therefore, in the airflow dynamics and simulation of wind loads before establishing an accurate wind speed model is crucial. At present, the application for wind turbines COMSOL fan, fan blades and wind load simulation field, the extremely important wind speed model is not perfect, most of the research is confined to a single constant wind speed, wind speed virtually ignored the magnitude and direction of change, on changes over time and space at the same time is one of the few studies of wind, so find a way to accurately describe the range of wind speeds, and can be combined well with COMSOL method can greatly improve the aerodynamic performance of wind turbines the overall level of .

scholarly journals PI and LQR controllers for Frequency Regulation including Wind Generation

2018 ◽  
Vol 8 (5) ◽  
pp. 3711 ◽  
Author(s):  
Semaria Ruiz ◽  
Julian Patiño ◽  
Jairo Espinosa
Keyword(s):  
Power Systems ◽  
Wind Turbines ◽  
Frequency Control ◽  
Test System ◽  
Performance Comparison ◽  
Load Frequency Control ◽  
Superior Performance ◽  
Frequency Regulation ◽  
Control Effort ◽  
Load Frequency

<pre>The increasing use of renewable technologies such as wind turbines in power systems may require the contribution of these new sources into grid ancillary services, such as Load Frequency Control. Hence, this work dealt with the performance comparison of two traditional control structures, PI and <span>LQR</span>, for secondary regulation of Load Frequency Control with the participation of variable-speed wind turbines. For this purpose, the doubly-fed induction generator wind turbine was modeled with additional control loops for emulation of the inertial response of conventional machines for frequency regulation tasks. Performance of proposed strategies was verified through simulation in a benchmark adapted from the <span>WSCC</span> 3 machines 9-bus test system. Results showed overall superior performance for <span>LQR</span> controller, although requiring more strenuous control effort from conventional units than PI control.</pre>

scholarly journals Analysis of the Patent of a Protective Cover for Vertical-Axis Wind Turbines (VAWTs): Simulations of Wind Flow

2020 ◽  
Vol 12 (18) ◽  
pp. 7818
Author(s):  
Jose Alberto Moleón Baca ◽  
Antonio Jesús Expósito González ◽  
Candido Gutiérrez Montes
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
High Speed ◽  
Experimental Tests ◽  
Weather Conditions ◽  
Vertical Axis ◽  
Good Alternative ◽  
Wind Speeds ◽  
Vertical Axis Wind Turbines

This paper presents a numerical and experimental analysis of the patent of a device to be used in vertical-axis wind turbines (VAWTs) under extreme wind conditions. The device consists of two hemispheres interconnected by a set of conveniently implemented variable section ducts through which the wind circulates to the blades. Furthermore, the design of the cross-section of the ducts allows the control of the wind speed inside the device. These ducts are intended to work as diffusers or nozzles, depending on the needs of the installation site. Simulations were performed for the case of high-speed external wind, for which the ducts act as diffusers to reduce wind speed and maintain a well-functioning internal turbine. Four different patent designs were analyzed, focusing on turbine performance and generated power. The results indicate that the patent allows the generation of electric power for a greater range of wind speeds than with a normal wind turbine. The results support that this patent may be a good alternative for wind power generation in geographic areas with extreme weather conditions or with maintained or strong gusty wind. Experimental tests were carried out on the movement of the blades using the available model. Finally, the power curve of the model of this wind turbine was obtained.

Increased Power Capture by Rotor Speed–Dependent Yaw Control of Wind Turbines

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Knud A. Kragh ◽  
Paul A. Fleming ◽  
Andrew K. Scholbrock
Keyword(s):  
Wind Turbines ◽  
Rotor Speed ◽  
Wind Speeds ◽  
Yaw Control ◽  
Correction Scheme ◽  
Power Capture ◽  
Horizontal Axis Wind Turbines ◽  
Power Yield ◽  
Additional Costs ◽  
Rotor Axis

When extracting energy from the wind using upwind, horizontal-axis wind turbines, a primary condition for ensuring maximum power yield is the ability to align the rotor axis with the dominating wind direction. Attempts have been made to improve the yaw alignment of wind turbines by applying advanced measurement technologies, such as light detection and ranging systems. However, application of advanced measurement equipment is associated with additional costs and increased system complexity. This study is focused on assessing the current performance of an operating turbine and exploring how the yaw alignment can be improved using measurements from the existing standard measurements system. By analyzing data from a case turbine and a corresponding meteorological mast, a correction scheme for the original yaw control system is suggested. The correction scheme is applied to the case turbine and tested. Results show that, with the correction scheme in place, the yaw alignment of the case turbine is improved and the yaw error is reduced to the vicinity of zero degrees. As a result of the improved yaw alignment, an increased power capture is observed for below-rated wind speeds.

scholarly journals Results from a wake-steering experiment at a commercial wind plant: investigating the wind speed dependence of wake-steering performance

2021 ◽  
Vol 6 (6) ◽  
pp. 1427-1453
Author(s):  
Eric Simley ◽  
Paul Fleming ◽  
Nicolas Girard ◽  
Lucas Alloin ◽  
Emma Godefroy ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Direction ◽  
Wind Farm ◽  
Poor Performance ◽  
Power Production ◽  
Wind Rose ◽  
Wind Speeds ◽  
Variability Model

Abstract. Wake steering is a wind farm control strategy in which upstream wind turbines are misaligned with the wind to redirect their wakes away from downstream turbines, thereby increasing the net wind plant power production and reducing fatigue loads generated by wake turbulence. In this paper, we present results from a wake-steering experiment at a commercial wind plant involving two wind turbines spaced 3.7 rotor diameters apart. During the 3-month experiment period, we estimate that wake steering reduced wake losses by 5.6 % for the wind direction sector investigated. After applying a long-term correction based on the site wind rose, the reduction in wake losses increases to 9.3 %. As a function of wind speed, we find large energy improvements near cut-in wind speed, where wake steering can prevent the downstream wind turbine from shutting down. Yet for wind speeds between 6–8 m/s, we observe little change in performance with wake steering. However, wake steering was found to improve energy production significantly for below-rated wind speeds from 8–12 m/s. By measuring the relationship between yaw misalignment and power production using a nacelle lidar, we attribute much of the improvement in wake-steering performance at higher wind speeds to a significant reduction in the power loss of the upstream turbine as wind speed increases. Additionally, we find higher wind direction variability at lower wind speeds, which contributes to poor performance in the 6–8 m/s wind speed bin because of slow yaw controller dynamics. Further, we compare the measured performance of wake steering to predictions using the FLORIS (FLOw Redirection and Induction in Steady State) wind farm control tool coupled with a wind direction variability model. Although the achieved yaw offsets at the upstream wind turbine fall short of the intended yaw offsets, we find that they are predicted well by the wind direction variability model. When incorporating the expected yaw offsets, estimates of the energy improvement from wake steering using FLORIS closely match the experimental results.

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